diff --git a/lang/pc/libpc/LIST b/lang/pc/libpc/LIST
deleted file mode 100644
index 297fe8bce..000000000
--- a/lang/pc/libpc/LIST
+++ /dev/null
@@ -1,73 +0,0 @@
-tail_pc.a
-abi.c
-abl.c
-abr.c
-arg.c
-ass.c
-asz.c
-atn.c
-bcp.c
-bts.e
-buff.c
-clock.c
-diag.c
-dis.c
-efl.c
-eln.c
-encaps.e
-exp.c
-get.c
-gto.e
-hlt.c
-ini.c
-catch.c
-log.c
-mdi.c
-mdl.c
-new.c
-nobuff.c
-notext.c
-opn.c
-hol0.e
-pac.c
-pclose.c
-pcreat.c
-pentry.c
-perrno.c
-pexit.c
-popen.c
-cls.c
-put.c
-rdc.c
-rdl.c
-rdr.c
-rdi.c
-rln.c
-rf.c
-rnd.c
-sav.e
-sig.e
-sin.c
-sqt.c
-fef.e
-string.c
-trap.e
-unp.c
-uread.c
-uwrite.c
-wdw.c
-incpt.c
-wrc.c
-wrf.c
-wri.c
-wrl.c
-wrr.c
-cvt.c
-fif.e
-wrz.c
-wrs.c
-outcpt.c
-wf.c
-nfa.c
-rcka.c
-trp.e
diff --git a/lang/pc/libpc/abi.c b/lang/pc/libpc/abi.c
index ae5bd8271..9971b292f 100644
--- a/lang/pc/libpc/abi.c
+++ b/lang/pc/libpc/abi.c
@@ -17,8 +17,9 @@
  */
 
 /* Author: J.W. Stevenson */
+#include "pc.h"
 
-int _abi(i) int i;
+int _abi(int i)
 {
 	return (i >= 0 ? i : -i);
 }
diff --git a/lang/pc/libpc/abl.c b/lang/pc/libpc/abl.c
index 50a5fb285..0e9bc5708 100644
--- a/lang/pc/libpc/abl.c
+++ b/lang/pc/libpc/abl.c
@@ -17,8 +17,9 @@
  */
 
 /* Author: J.W. Stevenson */
+#include "pc.h"
 
-long _abl(i) long i;
+long _abl(long i)
 {
 	return (i >= 0 ? i : -i);
 }
diff --git a/lang/pc/libpc/abr.c b/lang/pc/libpc/abr.c
index 3bde9f69c..a95a13948 100644
--- a/lang/pc/libpc/abr.c
+++ b/lang/pc/libpc/abr.c
@@ -17,8 +17,9 @@
  */
 
 /* Author: J.W. Stevenson */
+#include "pc.h"
 
-double _abr(r) double r;
+double _abr(double r)
 {
 	return (r >= 0 ? r : -r);
 }
diff --git a/lang/pc/libpc/arg.c b/lang/pc/libpc/arg.c
index e512c534a..43c6c15f1 100644
--- a/lang/pc/libpc/arg.c
+++ b/lang/pc/libpc/arg.c
@@ -17,29 +17,26 @@
  */
 
 /* Author: J.W. Stevenson */
+#include "pc.h"
 
 /* function argc:integer; extern; */
 /* function argv(i:integer):string; extern; */
 /* procedure argshift; extern; */
 /* function environ(i:integer):string; extern; */
 
-extern int _pargc;
-extern char** _pargv;
-extern char** _penvp;
-
-int argc()
+int argc(void)
 {
 	return (_pargc);
 }
 
-char* argv(i)
+char* argv(int i)
 {
 	if (i >= _pargc)
 		return (0);
 	return (_pargv[i]);
 }
 
-argshift()
+void argshift(void)
 {
 
 	if (_pargc > 1)
@@ -48,15 +45,3 @@ argshift()
 		_pargv++;
 	}
 }
-
-char* environ(i)
-{
-	char** p;
-	char* q;
-
-	if (p = _penvp)
-		while (q = *p++)
-			if (i-- < 0)
-				return (q);
-	return (0);
-}
diff --git a/lang/pc/libpc/ass.c b/lang/pc/libpc/ass.c
index c702d2642..3f888344a 100644
--- a/lang/pc/libpc/ass.c
+++ b/lang/pc/libpc/ass.c
@@ -19,12 +19,9 @@
 /* Author: J.W. Stevenson */
 
 #include <em_abs.h>
-#include <pc_err.h>
+#include "pc.h"
 
-extern char* _hol0();
-extern _trp();
-
-_ass(line, bool) int line, bool;
+void _ass(int line, int bool)
 {
 
 	if (bool == 0)
diff --git a/lang/pc/libpc/asz.c b/lang/pc/libpc/asz.c
index 304d13a18..9148e9b8b 100644
--- a/lang/pc/libpc/asz.c
+++ b/lang/pc/libpc/asz.c
@@ -16,16 +16,11 @@
  *
  */
 
+#include "pc.h"
+
 /* Author: J.W. Stevenson */
 
-struct descr
-{
-	int low;
-	int diff;
-	int size;
-};
-
-int _asz(dp) struct descr* dp;
+int _asz(struct descr* dp)
 {
 	return (dp->size * (dp->diff + 1));
 }
diff --git a/lang/pc/libpc/atn.c b/lang/pc/libpc/atn.c
index 2d05c7b4a..855dd2f80 100644
--- a/lang/pc/libpc/atn.c
+++ b/lang/pc/libpc/atn.c
@@ -10,12 +10,9 @@
 #define __NO_DEFS
 #include <math.h>
 
-#if __STDC__
-#include <pc_math.h>
-#endif
+#include "pc.h"
 
-double
-    _atn(x) double x;
+double _atn(double x)
 {
 	/*	Algorithm and coefficients from:
 			"Software manual for the elementary functions"
diff --git a/lang/pc/libpc/bcp.c b/lang/pc/libpc/bcp.c
index cb8d6a240..96dfc2b54 100644
--- a/lang/pc/libpc/bcp.c
+++ b/lang/pc/libpc/bcp.c
@@ -17,9 +17,9 @@
  */
 
 /* Author: J.W. Stevenson */
+#include "pc.h"
 
-int _bcp(sz, y, x) int sz;
-unsigned char *y, *x;
+int _bcp(int sz, unsigned char* y, unsigned char* x)
 {
 
 	while (--sz >= 0)
diff --git a/lang/pc/libpc/buff.c b/lang/pc/libpc/buff.c
index fdead046e..606ee088a 100644
--- a/lang/pc/libpc/buff.c
+++ b/lang/pc/libpc/buff.c
@@ -18,13 +18,11 @@
 
 /* Author: J.W. Stevenson */
 
-#include <pc_file.h>
-
-extern _flush();
+#include "pc.h"
 
 /* procedure buff(var f:file of ?); */
 
-buff(f) struct file* f;
+void buff(struct file* f)
 {
 	int sz;
 
diff --git a/lang/pc/libpc/catch.c b/lang/pc/libpc/catch.c
index 127994c40..4221f9891 100644
--- a/lang/pc/libpc/catch.c
+++ b/lang/pc/libpc/catch.c
@@ -20,11 +20,7 @@
 #include <errno.h>
 #include <unistd.h>
 #include <em_abs.h>
-#include <pc_err.h>
-#include <pc_file.h>
-
-/* to make it easier to patch ... */
-extern struct file* _curfil;
+#include "pc.h"
 
 static struct errm
 {
@@ -83,14 +79,8 @@ static struct errm
 	{ -1, 0 }
 };
 
-extern int _pargc;
-extern char** _pargv;
-extern char** _penvp;
 
-extern char* _hol0();
-extern _trp();
-
-_catch(erno) unsigned erno;
+void _catch(unsigned int erno)
 {
 	register struct errm* ep = &errors[0];
 	char *p, *q, *s, **qq;
diff --git a/lang/pc/libpc/clock.c b/lang/pc/libpc/clock.c
deleted file mode 100644
index bd57240ec..000000000
--- a/lang/pc/libpc/clock.c
+++ /dev/null
@@ -1,49 +0,0 @@
-/* $Id$ */
-/*
- * (c) copyright 1983 by the Vrije Universiteit, Amsterdam, The Netherlands.
- *
- *          This product is part of the Amsterdam Compiler Kit.
- *
- * Permission to use, sell, duplicate or disclose this software must be
- * obtained in writing. Requests for such permissions may be sent to
- *
- *      Dr. Andrew S. Tanenbaum
- *      Wiskundig Seminarium
- *      Vrije Universiteit
- *      Postbox 7161
- *      1007 MC Amsterdam
- *      The Netherlands
- *
- */
-
-/* Author: J.W. Stevenson */
-
-/* function clock:integer; extern; */
-
-extern int _times();
-
-struct tbuf
-{
-	long utime;
-	long stime;
-	long cutime;
-	long cstime;
-};
-
-#ifndef EM_WSIZE
-#define EM_WSIZE _EM_WSIZE
-#endif
-
-int clock()
-{
-	struct tbuf t;
-
-	_times(&t);
-	return ((int)(t.utime + t.stime) &
-#if EM_WSIZE <= 2
-	    077777
-#else
-	    0x7fffffffL
-#endif
-	    );
-}
diff --git a/lang/pc/libpc/cls.c b/lang/pc/libpc/cls.c
index dcf3e381d..2cf88fe83 100644
--- a/lang/pc/libpc/cls.c
+++ b/lang/pc/libpc/cls.c
@@ -20,15 +20,9 @@
 
 #include <stdlib.h>
 #include <unistd.h>
-#include <pc_file.h>
-#include <pc_err.h>
+#include "pc.h"
 
-extern struct file* _curfil;
-extern _trp();
-extern _flush();
-extern _outcpt();
-
-_xcls(f) struct file* f;
+void _xcls(struct file* f)
 {
 
 	if ((f->flags & WRBIT) == 0)
@@ -45,7 +39,7 @@ _xcls(f) struct file* f;
 	_flush(f);
 }
 
-_cls(f) struct file* f;
+void _cls(struct file* f)
 {
 #ifdef MAYBE
 	char* p;
diff --git a/lang/pc/libpc/cvt.c b/lang/pc/libpc/cvt.c
index bffe97eb5..2481a0f86 100644
--- a/lang/pc/libpc/cvt.c
+++ b/lang/pc/libpc/cvt.c
@@ -1,3 +1,5 @@
+#include "pc.h"
+
 /* $Id$ */
 #ifndef NOFLOAT
 
@@ -8,19 +10,16 @@
 #define DBL_MAX M_MAX_D
 #endif
 
-static char* cvt();
+static char* cvt(double value, int ndigit, int* decpt, int* sign, int ecvtflag);
+
 #define NDIGITS 128
 
-char*
-    _ecvt(value, ndigit, decpt, sign) double value;
-int ndigit, *decpt, *sign;
+char *_ecvt(double value, int ndigit, int *decpt, int *sign)
 {
 	return cvt(value, ndigit, decpt, sign, 1);
 }
 
-char*
-    _fcvt(value, ndigit, decpt, sign) double value;
-int ndigit, *decpt, *sign;
+char *_fcvt(double value, int ndigit, int *decpt, int *sign)
 {
 	return cvt(value, ndigit, decpt, sign, 0);
 }
@@ -40,9 +39,7 @@ static struct powers_of_10
 	1.0e0, 1.0e0, 0
 };
 
-static char*
-    cvt(value, ndigit, decpt, sign, ecvtflag) double value;
-int ndigit, *decpt, *sign;
+static char* cvt(double value, int ndigit, int* decpt, int* sign, int ecvtflag)
 {
 	static char buf[NDIGITS + 1];
 	register char* p = buf;
diff --git a/lang/pc/libpc/diag.c b/lang/pc/libpc/diag.c
index d4cffc0fd..69ca69c65 100644
--- a/lang/pc/libpc/diag.c
+++ b/lang/pc/libpc/diag.c
@@ -18,13 +18,12 @@
 
 /* Author: J.W. Stevenson */
 
-#include <pc_file.h>
+#include "pc.h"
 
 /* procedure diag(var f:text); */
 
-diag(f) struct file* f;
+void diag(struct file* f)
 {
-
 	f->ptr = f->bufadr;
 	f->flags = WRBIT | EOFBIT | ELNBIT | TXTBIT | MAGIC;
 	f->fname = "DIAG";
diff --git a/lang/pc/libpc/efl.c b/lang/pc/libpc/efl.c
index 8f3f7b1d3..280a59e57 100644
--- a/lang/pc/libpc/efl.c
+++ b/lang/pc/libpc/efl.c
@@ -20,14 +20,9 @@
 
 #include <stdlib.h>
 #include <errno.h>
-#include <pc_file.h>
-#include <pc_err.h>
+#include "pc.h"
 
-extern struct file* _curfil;
-extern _trp();
-extern _incpt();
-
-int _efl(f) struct file* f;
+int _efl(struct file* f)
 {
 
 	_curfil = f;
diff --git a/lang/pc/libpc/eln.c b/lang/pc/libpc/eln.c
index ec6f53e05..beba1dc69 100644
--- a/lang/pc/libpc/eln.c
+++ b/lang/pc/libpc/eln.c
@@ -18,13 +18,9 @@
 
 /* Author: J.W. Stevenson */
 
-#include <pc_file.h>
-#include <pc_err.h>
+#include "pc.h"
 
-extern _trp();
-extern _rf();
-
-int _eln(f) struct file* f;
+int _eln(struct file* f)
 {
 
 	_rf(f);
diff --git a/lang/pc/libpc/exp.c b/lang/pc/libpc/exp.c
index ab7eeb9a4..66def25e4 100644
--- a/lang/pc/libpc/exp.c
+++ b/lang/pc/libpc/exp.c
@@ -8,12 +8,10 @@
 /* $Id$ */
 #define __NO_DEFS
 #include <math.h>
-#include <pc_err.h>
-extern _trp();
+#include "pc.h"
 
 #if __STDC__
 #include <float.h>
-#include <pc_math.h>
 #define M_MIN_D DBL_MIN
 #define M_MAX_D DBL_MAX
 #define M_DMINEXP DBL_MIN_EXP
@@ -21,11 +19,8 @@ extern _trp();
 #undef HUGE
 #define HUGE 1e1000
 
-static double
-    Ldexp(fl, exp) double fl;
-int exp;
+static double Ldexp(double fl, int exp)
 {
-	extern double _fef();
 	int sign = 1;
 	int currexp;
 
@@ -57,8 +52,7 @@ int exp;
 	return sign * fl;
 }
 
-double
-    _exp(x) double x;
+double _exp(double x)
 {
 	/*	Algorithm and coefficients from:
 			"Software manual for the elementary functions"
diff --git a/lang/pc/libpc/get.c b/lang/pc/libpc/get.c
index 1b6c98f33..6c226f0e1 100644
--- a/lang/pc/libpc/get.c
+++ b/lang/pc/libpc/get.c
@@ -16,13 +16,9 @@
  *
  */
 
-#include <pc_file.h>
-#include <pc_err.h>
+#include "pc.h"
 
-extern _rf();
-extern _trp();
-
-_get(f) struct file* f;
+void _get(struct file* f)
 {
 
 	_rf(f);
diff --git a/lang/pc/libpc/hlt.c b/lang/pc/libpc/hlt.c
index 3e4fa0120..a761d51eb 100644
--- a/lang/pc/libpc/hlt.c
+++ b/lang/pc/libpc/hlt.c
@@ -18,14 +18,10 @@
 
 /* Author: J.W. Stevenson */
 
-#include <pc_file.h>
+#include <unistd.h>
+#include "pc.h"
 
-extern struct file** _extfl;
-extern int _extflc;
-extern _cls();
-extern _exit();
-
-_hlt(ecode) int ecode;
+void _hlt(int ecode)
 {
 	int i;
 
diff --git a/lang/pc/libpc/incpt.c b/lang/pc/libpc/incpt.c
index 351ec7500..8e549d202 100644
--- a/lang/pc/libpc/incpt.c
+++ b/lang/pc/libpc/incpt.c
@@ -21,14 +21,10 @@
 #include <stdlib.h>
 #include <errno.h>
 #include <unistd.h>
-#include <pc_file.h>
-#include <pc_err.h>
+#include "pc.h"
 
-extern _trp();
-
-_incpt(f) struct file* f;
+void _incpt(struct file* f)
 {
-
 	if (f->flags & EOFBIT)
 		_trp(EEOF);
 	f->flags |= WINDOW;
diff --git a/lang/pc/libpc/ini.c b/lang/pc/libpc/ini.c
index 6f08daa83..d7e7e4d96 100644
--- a/lang/pc/libpc/ini.c
+++ b/lang/pc/libpc/ini.c
@@ -18,24 +18,21 @@
 
 /* Author: J.W. Stevenson */
 
-#include <pc_file.h>
-#include <pc_err.h>
+#include "pc.h"
 
-extern (*_sig())();
-extern _catch();
-
-struct file** _extfl;
-int _extflc; /* number of external files */
-char* _m_lb; /* LB of _m_a_i_n */
-struct file* _curfil; /* points to file struct in case of errors */
 int _pargc;
 char** _pargv;
 char** _penvp;
+
+char* _m_lb; /* LB of _m_a_i_n */
+struct file* _curfil; /* points to file struct in case of errors */
+
+int _extflc;
+struct file** _extfl;
+
 int _fp_hook = 1; /* This is for Minix, but does not harm others */
 
-_ini(args, c, p, mainlb) char* args, *mainlb;
-int c;
-struct file** p;
+void _ini(char *args, int c, struct file **p, char *mainlb)
 {
 	struct file* f;
 
diff --git a/lang/pc/libpc/log.c b/lang/pc/libpc/log.c
index de1e8083c..2ee2270a1 100644
--- a/lang/pc/libpc/log.c
+++ b/lang/pc/libpc/log.c
@@ -9,17 +9,15 @@
 
 #define __NO_DEFS
 #include <math.h>
-#include <pc_err.h>
+#include "pc.h"
 
 #if __STDC__
-#include <pc_math.h>
 #include <float.h>
 #endif
 #undef HUGE
 #define HUGE 1e1000
 
-double
-    _log(x) double x;
+double _log(double x)
 {
 	/*	Algorithm and coefficients from:
 			"Software manual for the elementary functions"
@@ -37,7 +35,6 @@ double
 		1.0
 	};
 
-	extern double _fef();
 	double znum, zden, z, w;
 	int exponent;
 
diff --git a/lang/pc/libpc/mdi.c b/lang/pc/libpc/mdi.c
index 9b119da45..be0160b9f 100644
--- a/lang/pc/libpc/mdi.c
+++ b/lang/pc/libpc/mdi.c
@@ -18,11 +18,9 @@
 
 /* Author: J.W. Stevenson */
 
-#include <pc_err.h>
+#include "pc.h"
 
-extern _trp();
-
-int _mdi(j, i) int j, i;
+int _mdi(int j, int i)
 {
 
 	if (j <= 0)
@@ -33,7 +31,7 @@ int _mdi(j, i) int j, i;
 	return (i);
 }
 
-long _mdil(j, i) long j, i;
+long _mdil(long j, long i)
 {
 
 	if (j <= 0)
@@ -44,7 +42,7 @@ long _mdil(j, i) long j, i;
 	return (i);
 }
 
-int _dvi(j, i) unsigned int j, i;
+int _dvi(unsigned int j, unsigned int i)
 {
 	int neg = 0;
 
@@ -64,7 +62,7 @@ int _dvi(j, i) unsigned int j, i;
 	return i;
 }
 
-long _dvil(j, i) unsigned long j, i;
+long _dvil(unsigned long j, unsigned long i)
 {
 	int neg = 0;
 
diff --git a/lang/pc/libpc/mdl.c b/lang/pc/libpc/mdl.c
index c7acd5c3d..1c87577fc 100644
--- a/lang/pc/libpc/mdl.c
+++ b/lang/pc/libpc/mdl.c
@@ -18,11 +18,9 @@
 
 /* Author: J.W. Stevenson */
 
-#include <pc_err.h>
+#include "pc.h"
 
-extern _trp();
-
-long _mdl(j, i) long j, i;
+long _mdl(long j, long i)
 {
 
 	if (j <= 0)
diff --git a/lang/pc/libpc/new.c b/lang/pc/libpc/new.c
index faeb70c62..9ce78d41d 100644
--- a/lang/pc/libpc/new.c
+++ b/lang/pc/libpc/new.c
@@ -1,8 +1,6 @@
 #include <stdlib.h>
 #include <em_abs.h>
-#include <pc_err.h>
-
-extern void _trp(int); /* called on error */
+#include "pc.h"
 
 void _new(int n, void** ptr)
 {
diff --git a/lang/pc/libpc/nfa.c b/lang/pc/libpc/nfa.c
index d16f6332d..a876c7ee3 100644
--- a/lang/pc/libpc/nfa.c
+++ b/lang/pc/libpc/nfa.c
@@ -6,11 +6,9 @@
 
 /* Author: Hans van Eck */
 
-#include <pc_err.h>
+#include "pc.h"
 
-extern _trp();
-
-_nfa(bool)
+void _nfa(int bool)
 {
 	if (!bool)
 		_trp(EFUNASS);
diff --git a/lang/pc/libpc/nobuff.c b/lang/pc/libpc/nobuff.c
index 934e396c8..1f3967988 100644
--- a/lang/pc/libpc/nobuff.c
+++ b/lang/pc/libpc/nobuff.c
@@ -18,13 +18,11 @@
 
 /* Author: J.W. Stevenson */
 
-#include <pc_file.h>
-
-extern _flush();
+#include "pc.h"
 
 /* procedure nobuff(var f:file of ?); */
 
-nobuff(f) struct file* f;
+void nobuff(struct file* f)
 {
 
 	if ((f->flags & (0377 | WRBIT)) != (MAGIC | WRBIT))
diff --git a/lang/pc/libpc/notext.c b/lang/pc/libpc/notext.c
index 3a22f98a0..2c0360913 100644
--- a/lang/pc/libpc/notext.c
+++ b/lang/pc/libpc/notext.c
@@ -16,9 +16,9 @@
  *
  */
 
-#include <pc_file.h>
+#include "pc.h"
 
-notext(f) struct file* f;
+void notext(struct file* f)
 {
 	f->flags &= ~TXTBIT;
 }
diff --git a/lang/pc/libpc/opn.c b/lang/pc/libpc/opn.c
index dd2ea7418..f39189a63 100644
--- a/lang/pc/libpc/opn.c
+++ b/lang/pc/libpc/opn.c
@@ -19,22 +19,11 @@
 /* Author: J.W. Stevenson */
 
 #include <stdlib.h>
+#include <fcntl.h>
 #include <unistd.h>
-#include <pc_file.h>
-#include <pc_err.h>
+#include "pc.h"
 
-extern struct file** _extfl;
-extern int _extflc;
-extern struct file* _curfil;
-extern int _pargc;
-extern char** _pargv;
-extern char** _penvp;
-
-extern _cls();
-extern _xcls();
-extern _trp();
-
-static int tmpfil()
+static int tmpfil(void)
 {
 	static char namebuf[] = "/tmp/plf.xxxxx";
 	int i;
@@ -55,15 +44,13 @@ static int tmpfil()
 		goto error;
 	if ((i = open(p, 2)) < 0)
 		goto error;
-	if (remove(p) != 0)
+	if (unlink(p) != 0)
 	error:
 		_trp(EREWR);
 	return (i);
 }
 
-static int initfl(descr, sz, f) int descr;
-int sz;
-struct file* f;
+static int initfl(int descr, int sz, struct file* f)
 {
 	int i;
 
@@ -117,16 +104,14 @@ struct file* f;
 	return (1);
 }
 
-_opn(sz, f) int sz;
-struct file* f;
+void _opn(int sz, struct file* f)
 {
 
 	if (initfl(MAGIC, sz, f))
 		f->count = 0;
 }
 
-_cre(sz, f) int sz;
-struct file* f;
+void _cre(int sz, struct file* f)
 {
 
 	if (initfl(WRBIT | EOFBIT | ELNBIT | MAGIC, sz, f))
diff --git a/lang/pc/libpc/outcpt.c b/lang/pc/libpc/outcpt.c
index 1e7693bc0..18993bf0a 100644
--- a/lang/pc/libpc/outcpt.c
+++ b/lang/pc/libpc/outcpt.c
@@ -21,12 +21,9 @@
 #include <stdlib.h>
 #include <errno.h>
 #include <unistd.h>
-#include <pc_file.h>
-#include <pc_err.h>
+#include "pc.h"
 
-extern _trp();
-
-_flush(f) struct file* f;
+void _flush(struct file* f)
 {
 	int i, n;
 
@@ -41,7 +38,7 @@ _flush(f) struct file* f;
 		_trp(EWRITE);
 }
 
-_outcpt(f) struct file* f;
+void _outcpt(struct file* f)
 {
 
 	f->flags &= ~ELNBIT;
diff --git a/lang/pc/libpc/pac.c b/lang/pc/libpc/pac.c
index 22cedbf88..a779c0ffc 100644
--- a/lang/pc/libpc/pac.c
+++ b/lang/pc/libpc/pac.c
@@ -18,9 +18,7 @@
 
 /* Author: J.W. Stevenson */
 
-#include <pc_err.h>
-
-extern _trp();
+#include "pc.h"
 
 #define assert(x) /* nothing */
 
@@ -28,16 +26,7 @@ extern _trp();
 #define EM_WSIZE _EM_WSIZE
 #endif
 
-struct descr
-{
-	int low;
-	int diff;
-	int size;
-};
-
-_pac(ad, zd, zp, i, ap) int i;
-struct descr *ad, *zd;
-char *zp, *ap;
+void _pac(struct descr *ad, struct descr *zd, char *zp, int i, char *ap)
 {
 
 	if (zd->diff > ad->diff || (i -= ad->low) < 0 || (i + zd->diff) > ad->diff)
diff --git a/lang/pc/libpc/pc.h b/lang/pc/libpc/pc.h
index b3f533eab..a38c62637 100644
--- a/lang/pc/libpc/pc.h
+++ b/lang/pc/libpc/pc.h
@@ -5,11 +5,36 @@
 #include "pc_file.h"
 #include "pc_math.h"
 
+struct descr
+{
+	int low;
+	int diff;
+	int size;
+};
+
+struct array_descr
+{
+	int lbound;
+	unsigned n_elts_min_one;
+	unsigned size; /* doesn't really matter */
+};
+
+
+extern int _extflc;
+extern struct file** _extfl;
+
+extern struct file* _curfil;
+extern int _pargc;
+extern char** _pargv;
+extern char** _penvp;
+
+extern char* _m_lb; /* LB of _m_a_i_n */
+extern struct file* _curfil; /* points to file struct in case of errors */
+
 extern char *_ecvt(double value, int ndigit, int *decpt, int *sign);
 extern char *_fcvt(double value, int ndigit, int *decpt, int *sign);
 extern char *_wdw(struct file *f);
 extern char *argv(int i);
-extern char *environ(int i);
 extern char *strbuf(char *s);
 extern double _abr(double r);
 extern double _atn(double x);
@@ -18,67 +43,25 @@ extern double _exp(double x);
 extern double _log(double x);
 extern double _rdr(struct file *f);
 extern double _rnd(double r);
+extern void _sig(void (*)(unsigned int));
 extern double _sin(double x);
 extern double _sqt(double x);
-extern int _abi(int i);
-extern int _ass(int line, int bool);
-extern int _asz(struct descr *dp);
-extern int _bcp(int sz, unsigned char *y, unsigned char *x);
-extern int _catch(unsigned erno);
-extern int _cls(struct file *f);
-extern int _cre(int sz, struct file *f);
-extern int _dvi(unsigned int j, unsigned int i);
-extern int _efl(struct file *f);
-extern int _eln(struct file *f);
-extern int _flush(struct file *f);
-extern int _fstdig(struct file *f);
-extern int _get(struct file *f);
-extern int _getint(struct file *f);
-extern int _getsig(struct file *f);
-extern int _hlt(int ecode);
-extern int _incpt(struct file *f);
-extern int _ini(char *args, int c, struct file **p, char *mainlb);
-extern int _mdi(int j, int i);
-extern int _nfa(int bool);
-extern int _nxtdig(struct file *f);
-extern int _opn(int sz, struct file *f);
-extern int _outcpt(struct file *f);
-extern int _pac(struct descr *ad, struct descr *zd, char *zp, int i, char *ap);
-extern int _pag(struct file *f);
-extern int _put(struct file *f);
-extern int _rcka(struct array_descr *descr, int index);
-extern int _rdc(struct file *f);
-extern int _rdi(struct file *f);
-extern int _rf(struct file *f);
-extern int _rln(struct file *f);
-extern int _skipsp(struct file *f);
-extern int _unp(struct descr *ad, struct descr *zd, int i, char *ap, char *zp, int noext);
-extern int _wf(struct file *f);
-extern int _wln(struct file *f);
-extern int _wrc(int c, struct file *f);
-extern int _wrf(int n, int w, double r, struct file *f);
-extern int _wri(int i, struct file *f);
-extern int _wrl(long l, struct file *f);
-extern int _wrr(double r, struct file *f);
-extern int _wsl(int w, long l, struct file *f);
-extern int _wsr(int w, double r, struct file *f);
-extern int _xcls(struct file *f);
+extern void _xcls(struct file *f);
 extern int argc(void);
-extern int argshift(void);
-extern int buff(struct file *f);
-extern int clock(void);
-extern int diag(struct file *f);
-extern int nobuff(struct file *f);
-extern int notext(struct file *f);
-extern int pclose(struct file *f);
-extern int pcreat(struct file *f, char *s);
+extern void argshift(void);
+extern void buff(struct file *f);
+extern void diag(struct file *f);
+extern void nobuff(struct file *f);
+extern void notext(struct file *f);
+extern void pclose(struct file *f);
+extern void pcreat(struct file *f, char *s);
 extern int perrno(void);
-extern int popen(struct file *f, char *s);
-extern int procentry(char *name);
-extern int procexit(char *name);
+extern void popen(struct file *f, char *s);
+extern void procentry(char *name);
+extern void procexit(char *name);
 extern int strfetch(char *s, int i);
 extern int strlen(char *s);
-extern int strstore(char *s, int i, int c);
+extern void strstore(char *s, int i, int c);
 extern int strtobuf(char *s, char *b, int l);
 extern int uread(int fd, char *b, int n);
 extern int uwrite(int fd, char *b, int n);
@@ -87,16 +70,62 @@ extern long _dvil(unsigned long j, unsigned long i);
 extern long _mdil(long j, long i);
 extern long _mdl(long j, long i);
 extern long _rdl(struct file *f);
+extern int _abi(int i);
+extern void _ass(int line, int bool);
+extern int _asz(struct descr *dp);
+extern int _bcp(int sz, unsigned char *y, unsigned char *x);
+extern void _catch(unsigned erno);
+extern void _cls(struct file *f);
+extern void _cre(int sz, struct file *f);
 extern void _dis(int n, void **ptr);
+extern int _dvi(unsigned int j, unsigned int i);
+extern int _efl(struct file *f);
+extern int _eln(struct file *f);
+extern double _fef(double fl, int* res);
+extern double _fif(double f1, double f2, double* f3);
+extern void _flush(struct file *f);
+extern int _fstdig(struct file *f);
+extern void _get(struct file *f);
+extern int _getint(struct file *f);
+extern int _getsig(struct file *f);
+extern void _hlt(int ecode);
+extern void _incpt(struct file *f);
+extern void _ini(char *args, int c, struct file **p, char *mainlb);
+extern int _mdi(int j, int i);
 extern void _new(int n, void **ptr);
+extern void _nfa(int bool);
+extern int _nxtdig(struct file *f);
+extern void _opn(int sz, struct file *f);
+extern void _outcpt(struct file *f);
+extern void _pac(struct descr *ad, struct descr *zd, char *zp, int i, char *ap);
+extern void _pag(struct file *f);
+extern void _put(struct file *f);
+extern void _rcka(struct array_descr *descr, int index);
+extern int _rdc(struct file *f);
+extern int _rdi(struct file *f);
+extern void _rf(struct file *f);
+extern void _rln(struct file *f);
+extern void _skipsp(struct file *f);
 extern void _trp(int trapno);
+extern void _unp(struct descr *ad, struct descr *zd, int i, char *ap, char *zp, int noext);
+extern void _wf(struct file *f);
+extern void _wln(struct file *f);
 extern void _wrb(int b, struct file *f);
+extern void _wrc(int c, struct file *f);
+extern void _wrf(int n, int w, double r, struct file *f);
+extern void _wri(int i, struct file *f);
+extern void _wrl(long l, struct file *f);
+extern void _wrr(double r, struct file *f);
 extern void _wrs(int len, char *s, struct file *f);
 extern void _wrz(char *s, struct file *f);
 extern void _wsb(int w, int b, struct file* f);
 extern void _wsc(int w, char c, struct file* f);
+extern void _wsi(int w, int i, struct file* f);
+extern void _wsl(int w, long l, struct file *f);
+extern void _wsr(int w, double r, struct file *f);
 extern void _wss(int w, int len, char* s, struct file* f);
 extern void _wstrin(int width, int len, char* buf, struct file* f);
 extern void _wsz(int w, char* s, struct file* f);
+extern char* _hol0(void);
 
 #endif 
diff --git a/lang/pc/libpc/pclose.c b/lang/pc/libpc/pclose.c
index 4f94168d9..270e7e5b0 100644
--- a/lang/pc/libpc/pclose.c
+++ b/lang/pc/libpc/pclose.c
@@ -16,13 +16,11 @@
  *
  */
 
-#include <pc_file.h>
-
-extern _cls();
+#include "pc.h"
 
 /* procedure pclose(var f:file of ??); */
 
-pclose(f) struct file* f;
+void pclose(struct file* f)
 {
 	_cls(f);
 }
diff --git a/lang/pc/libpc/pcreat.c b/lang/pc/libpc/pcreat.c
index 3b522d1ff..39c8caa7c 100644
--- a/lang/pc/libpc/pcreat.c
+++ b/lang/pc/libpc/pcreat.c
@@ -19,16 +19,11 @@
 /* Author: J.W. Stevenson */
 
 #include <unistd.h>
-#include <pc_file.h>
-#include <pc_err.h>
-
-extern _cls();
-extern _trp();
+#include "pc.h"
 
 /* procedure pcreat(var f:text; s:string); */
 
-pcreat(f, s) struct file* f;
-char* s;
+void pcreat(struct file* f, char* s)
 {
 
 	_cls(f); /* initializes _curfil */
diff --git a/lang/pc/libpc/pentry.c b/lang/pc/libpc/pentry.c
index 16ce893e6..bb3806d36 100644
--- a/lang/pc/libpc/pentry.c
+++ b/lang/pc/libpc/pentry.c
@@ -18,14 +18,9 @@
 
 /* Author: J.W. Stevenson */
 
-#include <pc_file.h>
+#include "pc.h"
 
-extern struct file** _extfl;
-extern _wrs();
-extern _wrz();
-extern _wln();
-
-procentry(name) char* name;
+void procentry(char* name)
 {
 	struct file* f;
 
diff --git a/lang/pc/libpc/perrno.c b/lang/pc/libpc/perrno.c
index 488cbc4fe..e57e8b350 100644
--- a/lang/pc/libpc/perrno.c
+++ b/lang/pc/libpc/perrno.c
@@ -19,8 +19,9 @@
 /* function perrno:integer; extern; */
 
 #include <errno.h>
+#include "pc.h"
 
-int perrno()
+int perrno(void)
 {
 	return (errno);
 }
diff --git a/lang/pc/libpc/pexit.c b/lang/pc/libpc/pexit.c
index a8d1d438d..b42f71e25 100644
--- a/lang/pc/libpc/pexit.c
+++ b/lang/pc/libpc/pexit.c
@@ -16,14 +16,9 @@
  *
  */
 
-#include <pc_file.h>
+#include "pc.h"
 
-extern struct file** _extfl;
-extern _wrs();
-extern _wrz();
-extern _wln();
-
-procexit(name) char* name;
+void procexit(char* name)
 {
 	struct file* f;
 
diff --git a/lang/pc/libpc/popen.c b/lang/pc/libpc/popen.c
index b180f9b67..2355913fa 100644
--- a/lang/pc/libpc/popen.c
+++ b/lang/pc/libpc/popen.c
@@ -18,19 +18,13 @@
 
 /* Author: J.W. Stevenson */
 
-#include <pc_file.h>
-#include <pc_err.h>
-
-extern _cls();
-extern _trp();
-extern int _open();
+#include "fcntl.h"
+#include "pc.h"
 
 /* procedure popen(var f:text; s:string); */
 
-popen(f, s) struct file* f;
-char* s;
+void popen(struct file* f, char* s)
 {
-
 	_cls(f); /* initializes _curfil */
 	f->ptr = f->bufadr;
 	f->flags = TXTBIT | MAGIC;
@@ -38,6 +32,6 @@ char* s;
 	f->size = 1;
 	f->count = 0;
 	f->buflen = PC_BUFLEN;
-	if ((f->ufd = _open(s, 0)) < 0)
+	if ((f->ufd = open(s, 0)) < 0)
 		_trp(ERESET);
 }
diff --git a/lang/pc/libpc/put.c b/lang/pc/libpc/put.c
index e127115d5..d2b832f94 100644
--- a/lang/pc/libpc/put.c
+++ b/lang/pc/libpc/put.c
@@ -16,12 +16,9 @@
  *
  */
 
-#include <pc_file.h>
+#include "pc.h"
 
-extern _wf();
-extern _outcpt();
-
-_put(f) struct file* f;
+void _put(struct file* f)
 {
 	_wf(f);
 	_outcpt(f);
diff --git a/lang/pc/libpc/rcka.c b/lang/pc/libpc/rcka.c
index 732f4c12a..055b7d1c5 100644
--- a/lang/pc/libpc/rcka.c
+++ b/lang/pc/libpc/rcka.c
@@ -6,18 +6,10 @@
 
 /* Author: Hans van Eck */
 
+#include "pc.h"
 #include <em_abs.h>
 
-extern _trp();
-
-struct array_descr
-{
-	int lbound;
-	unsigned n_elts_min_one;
-	unsigned size; /* doesn't really matter */
-};
-
-_rcka(descr, index) struct array_descr* descr;
+void _rcka(struct array_descr* descr, int index)
 {
 	if (index < descr->lbound || index > (int)descr->n_elts_min_one + descr->lbound)
 		_trp(EARRAY);
diff --git a/lang/pc/libpc/rdc.c b/lang/pc/libpc/rdc.c
index 27df316f1..ef7eb3051 100644
--- a/lang/pc/libpc/rdc.c
+++ b/lang/pc/libpc/rdc.c
@@ -16,12 +16,9 @@
  *
  */
 
-#include <pc_file.h>
+#include "pc.h"
 
-extern _rf();
-extern _incpt();
-
-int _rdc(f) struct file* f;
+int _rdc(struct file* f)
 {
 	int c;
 
diff --git a/lang/pc/libpc/rdi.c b/lang/pc/libpc/rdi.c
index eaf3117cf..33e1de897 100644
--- a/lang/pc/libpc/rdi.c
+++ b/lang/pc/libpc/rdi.c
@@ -18,20 +18,15 @@
 
 /* Author: J.W. Stevenson */
 
-#include <pc_file.h>
-#include <pc_err.h>
+#include "pc.h"
 
-extern _trp();
-extern _rf();
-extern _incpt();
-
-_skipsp(f) struct file* f;
+void _skipsp(struct file* f)
 {
 	while ((*f->ptr == ' ') || (*f->ptr == '\t'))
 		_incpt(f);
 }
 
-int _getsig(f) struct file* f;
+int _getsig(struct file* f)
 {
 	int sign;
 
@@ -40,7 +35,7 @@ int _getsig(f) struct file* f;
 	return (sign);
 }
 
-int _fstdig(f) struct file* f;
+int _fstdig(struct file* f)
 {
 	int ch;
 
@@ -53,7 +48,7 @@ int _fstdig(f) struct file* f;
 	return (ch);
 }
 
-int _nxtdig(f) struct file* f;
+int _nxtdig(struct file* f)
 {
 	int ch;
 
@@ -64,7 +59,7 @@ int _nxtdig(f) struct file* f;
 	return (ch);
 }
 
-int _getint(f) struct file* f;
+int _getint(struct file* f)
 {
 	int is_signed, i, ch;
 
@@ -77,7 +72,7 @@ int _getint(f) struct file* f;
 	return (is_signed ? i : -i);
 }
 
-int _rdi(f) struct file* f;
+int _rdi(struct file* f)
 {
 	_rf(f);
 	_skipsp(f);
diff --git a/lang/pc/libpc/rdl.c b/lang/pc/libpc/rdl.c
index 3cf731f5b..110d4130d 100644
--- a/lang/pc/libpc/rdl.c
+++ b/lang/pc/libpc/rdl.c
@@ -18,15 +18,9 @@
 
 /* Author: J.W. Stevenson */
 
-#include <pc_file.h>
+#include "pc.h"
 
-extern _rf();
-extern _skipsp();
-extern int _getsig();
-extern int _fstdig();
-extern int _nxtdig();
-
-long _rdl(f) struct file* f;
+long _rdl(struct file* f)
 {
 	int is_signed, ch;
 	long l;
diff --git a/lang/pc/libpc/rdr.c b/lang/pc/libpc/rdr.c
index 5c8ccec51..c8112fac8 100644
--- a/lang/pc/libpc/rdr.c
+++ b/lang/pc/libpc/rdr.c
@@ -18,22 +18,14 @@
 
 /* Author: J.W. Stevenson */
 
-#include <pc_file.h>
+#include "pc.h"
 
 #define BIG 1e17
 
-extern _rf();
-extern _incpt();
-extern _skipsp();
-extern int _getsig();
-extern int _getint();
-extern int _fstdig();
-extern int _nxtdig();
-
 static double r;
 static int pow10;
 
-static dig(ch) int ch;
+static void dig(int ch)
 {
 
 	if (r > BIG)
@@ -42,7 +34,7 @@ static dig(ch) int ch;
 		r = r * 10.0 + ch;
 }
 
-double _rdr(f) struct file* f;
+double _rdr(struct file* f)
 {
 	int i;
 	double e;
diff --git a/lang/pc/libpc/rf.c b/lang/pc/libpc/rf.c
index a90a9aeb5..498408836 100644
--- a/lang/pc/libpc/rf.c
+++ b/lang/pc/libpc/rf.c
@@ -16,14 +16,9 @@
  *
  */
 
-#include <pc_file.h>
-#include <pc_err.h>
+#include "pc.h"
 
-extern struct file* _curfil;
-extern _trp();
-extern _incpt();
-
-_rf(f) struct file* f;
+void _rf(struct file* f)
 {
 
 	_curfil = f;
diff --git a/lang/pc/libpc/rln.c b/lang/pc/libpc/rln.c
index 2c95f4415..20d61f53f 100644
--- a/lang/pc/libpc/rln.c
+++ b/lang/pc/libpc/rln.c
@@ -16,12 +16,9 @@
  *
  */
 
-#include <pc_file.h>
+#include "pc.h"
 
-extern _rf();
-extern _incpt();
-
-_rln(f) struct file* f;
+void _rln(struct file* f)
 {
 
 	_rf(f);
diff --git a/lang/pc/libpc/rnd.c b/lang/pc/libpc/rnd.c
index 67fe2f379..6709ce1f9 100644
--- a/lang/pc/libpc/rnd.c
+++ b/lang/pc/libpc/rnd.c
@@ -16,7 +16,9 @@
  *
  */
 
-double _rnd(r) double r;
+#include "pc.h"
+
+double _rnd(double r)
 {
 	return (r + (r < 0 ? -0.5 : 0.5));
 }
diff --git a/lang/pc/libpc/sin.c b/lang/pc/libpc/sin.c
index a483bed66..3b5965369 100644
--- a/lang/pc/libpc/sin.c
+++ b/lang/pc/libpc/sin.c
@@ -9,13 +9,9 @@
 
 #define __NO_DEFS
 #include <math.h>
+#include "pc.h"
 
-#if __STDC__
-#include <pc_math.h>
-#endif
-
-static double
-    sinus(x, cos_flag) double x;
+static double sinus(double x, int cos_flag)
 {
 	/*	Algorithm and coefficients from:
 			"Software manual for the elementary functions"
@@ -62,7 +58,6 @@ static double
 #define A2 -8.908910206761537356617e-6
 	{
 		double x1, x2;
-		extern double _fif();
 
 		_fif(y, 1.0, &y);
 		if (_fif(y, 0.5, &x1))
@@ -90,14 +85,12 @@ static double
 	return neg ? -x : x;
 }
 
-double
-    _sin(x) double x;
+double _sin(double x)
 {
 	return sinus(x, 0);
 }
 
-double
-    _cos(x) double x;
+double _cos(double x)
 {
 	if (x < 0)
 		x = -x;
diff --git a/lang/pc/libpc/sqt.c b/lang/pc/libpc/sqt.c
index efaf7053d..122bab100 100644
--- a/lang/pc/libpc/sqt.c
+++ b/lang/pc/libpc/sqt.c
@@ -8,16 +8,12 @@
 /* $Id$ */
 #define __NO_DEFS
 #include <math.h>
-#include <pc_err.h>
-extern _trp();
+#include "pc.h"
 
 #define NITER 5
 
-static double
-    Ldexp(fl, exp) double fl;
-int exp;
+static double Ldexp(double fl, int exp)
 {
-	extern double _fef();
 	int sign = 1;
 	int currexp;
 
@@ -49,10 +45,8 @@ int exp;
 	return sign * fl;
 }
 
-double
-    _sqt(x) double x;
+double _sqt(double x)
 {
-	extern double _fef();
 	int exponent;
 	double val;
 
diff --git a/lang/pc/libpc/string.c b/lang/pc/libpc/string.c
index 8cc8a68f5..0da9b4764 100644
--- a/lang/pc/libpc/string.c
+++ b/lang/pc/libpc/string.c
@@ -16,16 +16,18 @@
  *
  */
 
+#include "pc.h"
+
 /* function strbuf(var b:charbuf):string; */
 
-char* strbuf(s) char* s;
+char* strbuf(char* s)
 {
 	return (s);
 }
 
 /* function strtobuf(s:string; var b:charbuf; blen:integer):integer; */
 
-int strtobuf(s, b, l) char *s, *b;
+int strtobuf(char* s, char* b, int l)
 {
 	int i;
 
@@ -41,7 +43,7 @@ int strtobuf(s, b, l) char *s, *b;
 
 /* function strlen(s:string):integer; */
 
-int strlen(s) char* s;
+int strlen(char* s)
 {
 	int i;
 
@@ -53,14 +55,14 @@ int strlen(s) char* s;
 
 /* function strfetch(s:string; i:integer):char; */
 
-int strfetch(s, i) char* s;
+int strfetch(char* s, int i)
 {
 	return (s[i - 1]);
 }
 
 /* procedure strstore(s:string; i:integer; c:char); */
 
-strstore(s, i, c) char* s;
+void strstore(char* s, int i, int c)
 {
 	s[i - 1] = c;
 }
diff --git a/lang/pc/libpc/unp.c b/lang/pc/libpc/unp.c
index 3479fa70b..b335f78ee 100644
--- a/lang/pc/libpc/unp.c
+++ b/lang/pc/libpc/unp.c
@@ -18,9 +18,7 @@
 
 /* Author: J.W. Stevenson */
 
-#include <pc_err.h>
-
-extern _trp();
+#include "pc.h"
 
 #define assert(x) /* nothing */
 
@@ -28,17 +26,7 @@ extern _trp();
 #define EM_WSIZE _EM_WSIZE
 #endif
 
-struct descr
-{
-	int low;
-	int diff;
-	int size;
-};
-
-_unp(ad, zd, i, ap, zp, noext) int i;
-struct descr *ad, *zd;
-char *ap, *zp;
-int noext;
+void _unp(struct descr *ad, struct descr *zd, int i, char *ap, char *zp, int noext)
 {
 
 	if (zd->diff > ad->diff || (i -= ad->low) < 0 || (i + zd->diff) > ad->diff)
diff --git a/lang/pc/libpc/uread.c b/lang/pc/libpc/uread.c
index b20c3c0bb..c9de43867 100644
--- a/lang/pc/libpc/uread.c
+++ b/lang/pc/libpc/uread.c
@@ -20,9 +20,9 @@
 
 #include <stdlib.h>
 #include <unistd.h>
+#include "pc.h"
 
-int uread(fd, b, n) char* b;
-int fd, n;
+int uread(int fd, char* b, int n)
 {
 	return (read(fd, b, n));
 }
diff --git a/lang/pc/libpc/uwrite.c b/lang/pc/libpc/uwrite.c
index bf8381cd7..35451b707 100644
--- a/lang/pc/libpc/uwrite.c
+++ b/lang/pc/libpc/uwrite.c
@@ -20,9 +20,9 @@
 
 #include <stdlib.h>
 #include <unistd.h>
+#include "pc.h"
 
-int uwrite(fd, b, n) char* b;
-int fd, n;
+int uwrite(int fd, char* b, int n)
 {
 	return (write(fd, b, n));
 }
diff --git a/lang/pc/libpc/wdw.c b/lang/pc/libpc/wdw.c
index 0c45bf215..c91a6d775 100644
--- a/lang/pc/libpc/wdw.c
+++ b/lang/pc/libpc/wdw.c
@@ -16,14 +16,10 @@
  *
  */
 
-#include <pc_file.h>
+#include "pc.h"
 
-extern struct file* _curfil;
-extern _incpt();
-
-char* _wdw(f) struct file* f;
+char* _wdw(struct file* f)
 {
-
 	_curfil = f;
 	if ((f->flags & (WINDOW | WRBIT | 0377)) == MAGIC)
 		_incpt(f);
diff --git a/lang/pc/libpc/wf.c b/lang/pc/libpc/wf.c
index 945d72533..a554fcfef 100644
--- a/lang/pc/libpc/wf.c
+++ b/lang/pc/libpc/wf.c
@@ -16,13 +16,9 @@
  *
  */
 
-#include <pc_file.h>
-#include <pc_err.h>
+#include "pc.h"
 
-extern struct file* _curfil;
-extern _trp();
-
-_wf(f) struct file* f;
+void _wf(struct file* f)
 {
 
 	_curfil = f;
diff --git a/lang/pc/libpc/wrc.c b/lang/pc/libpc/wrc.c
index 437d73a54..9055050da 100644
--- a/lang/pc/libpc/wrc.c
+++ b/lang/pc/libpc/wrc.c
@@ -16,20 +16,16 @@
  *
  */
 
-#include <pc_file.h>
+#include "pc.h"
 
-extern _wf();
-extern _outcpt();
-
-_wrc(c, f) int c;
-struct file* f;
+void _wrc(int c, struct file* f)
 {
 	*f->ptr = c;
 	_wf(f);
 	_outcpt(f);
 }
 
-_wln(f) struct file* f;
+void _wln(struct file* f)
 {
 #ifdef CPM
 	_wrc('\r', f);
@@ -38,7 +34,7 @@ _wln(f) struct file* f;
 	f->flags |= ELNBIT;
 }
 
-_pag(f) struct file* f;
+void _pag(struct file* f)
 {
 	_wrc('\014', f);
 	f->flags |= ELNBIT;
diff --git a/lang/pc/libpc/wrf.c b/lang/pc/libpc/wrf.c
index 5c213c7c6..5662ad89b 100644
--- a/lang/pc/libpc/wrf.c
+++ b/lang/pc/libpc/wrf.c
@@ -18,11 +18,7 @@
 
 /* Author: J.W. Stevenson */
 
-#include <pc_err.h>
-#include <pc_file.h>
-
-extern _wstrin();
-extern char* _fcvt();
+#include "pc.h"
 
 #define assert(x) /* nothing */
 
@@ -36,9 +32,7 @@ extern char* _fcvt();
 #define FILL_CHAR '0' /* char printed if all of _fcvt() used */
 #define BUFSIZE HUGE_DIG + PREC_DIG + 3
 
-_wrf(n, w, r, f) int n, w;
-double r;
-struct file* f;
+void _wrf(int n, int w, double r, struct file* f)
 {
 	char *p, *b;
 	int s, d;
diff --git a/lang/pc/libpc/wri.c b/lang/pc/libpc/wri.c
index b027bc6f9..7a30a6ce9 100644
--- a/lang/pc/libpc/wri.c
+++ b/lang/pc/libpc/wri.c
@@ -16,10 +16,7 @@
  *
  */
 
-#include <pc_err.h>
-#include <pc_file.h>
-
-extern _wstrin();
+#include "pc.h"
 
 #ifndef EM_WSIZE
 #ifdef _EM_WSIZE
@@ -47,9 +44,7 @@ extern _wstrin();
 Something wrong here !
 #endif
 
-    _wsi(w, i, f) int w,
-    i;
-struct file* f;
+void _wsi(int w, int i, struct file* f)
 {
 	char* p;
 	int j;
@@ -75,8 +70,7 @@ struct file* f;
 	_wstrin(w, (int)(&buf[SZ] - p), p, f);
 }
 
-_wri(i, f) int i;
-struct file* f;
+void _wri(int i, struct file* f)
 {
 	_wsi(SZ, i, f);
 }
diff --git a/lang/pc/libpc/wrl.c b/lang/pc/libpc/wrl.c
index c5bfff928..eafb912ab 100644
--- a/lang/pc/libpc/wrl.c
+++ b/lang/pc/libpc/wrl.c
@@ -18,16 +18,10 @@
 
 /* Author: J.W. Stevenson */
 
-#include <pc_err.h>
-#include <pc_file.h>
+#include "pc.h"
+#include <limits.h>
 
-extern _wstrin();
-
-#define MAXNEGLONG -2147483648
-
-_wsl(w, l, f) int w;
-long l;
-struct file* f;
+void _wsl(int w, long l, struct file* f)
 {
 	char *p, c;
 	long j;
@@ -38,7 +32,7 @@ struct file* f;
 	p = &buf[11];
 	if ((j = l) < 0)
 	{
-		if (l == MAXNEGLONG)
+		if (l == LONG_MIN)
 		{
 			_wstrin(w, 11, "-2147483648", f);
 			return;
@@ -55,8 +49,7 @@ struct file* f;
 	_wstrin(w, (int)(&buf[11] - p), p, f);
 }
 
-_wrl(l, f) long l;
-struct file* f;
+void _wrl(long l, struct file* f)
 {
 	_wsl(11, l, f);
 }
diff --git a/lang/pc/libpc/wrr.c b/lang/pc/libpc/wrr.c
index 8f99062ca..c61ec2f5b 100644
--- a/lang/pc/libpc/wrr.c
+++ b/lang/pc/libpc/wrr.c
@@ -18,17 +18,11 @@
 
 /* Author: J.W. Stevenson */
 
-#include <pc_err.h>
-#include <pc_file.h>
-
-extern _wstrin();
-extern char* _ecvt();
+#include "pc.h"
 
 #define PREC_DIG 80 /* maximum digits produced by _ecvt() */
 
-_wsr(w, r, f) int w;
-double r;
-struct file* f;
+void _wsr(int w, double r, struct file* f)
 {
 	char *p, *b;
 	int s, d, i;
@@ -72,8 +66,7 @@ struct file* f;
 	_wstrin(w, (int)(p - buf), buf, f);
 }
 
-_wrr(r, f) double r;
-struct file* f;
+void _wrr(double r, struct file* f)
 {
 	_wsr(13, r, f);
 }
diff --git a/plat/cpm/include/unistd.h b/plat/cpm/include/unistd.h
index ea4f51c0f..99f1fb2d4 100644
--- a/plat/cpm/include/unistd.h
+++ b/plat/cpm/include/unistd.h
@@ -45,6 +45,7 @@ extern int open(const char* path, int access, ...);
 extern int creat(const char* path, mode_t mode);
 extern int read(int fd, void* buffer, size_t count);
 extern int write(int fd, void* buffer, size_t count);
+extern int unlink(const char* path);
 
 /* Unimplemented system calls (these are just prototypes to let the library
  * compile). */
diff --git a/plat/pc86/include/unistd.h b/plat/pc86/include/unistd.h
index 174c43ad0..77bdcf10d 100644
--- a/plat/pc86/include/unistd.h
+++ b/plat/pc86/include/unistd.h
@@ -46,6 +46,7 @@ extern int open(const char* path, int access, ...);
 extern int creat(const char* path, mode_t mode);
 extern int read(int fd, void* buffer, size_t count);
 extern int write(int fd, void* buffer, size_t count);
+extern int unlink(const char* path);
 
 /* Unimplemented system calls (these are just prototypes to let the library
  * compile). */
diff --git a/plat/pdpv7/include/unistd.h b/plat/pdpv7/include/unistd.h
index 2b48dd6bf..31167015f 100644
--- a/plat/pdpv7/include/unistd.h
+++ b/plat/pdpv7/include/unistd.h
@@ -67,6 +67,7 @@ extern int open(const char* path, int access, ...);
 extern int creat(const char* path, mode_t mode);
 extern int read(int fd, void* buffer, size_t count);
 extern int write(int fd, void* buffer, size_t count);
+extern int unlink(const char* path);
 
 /* Unimplemented system calls (these are just prototypes to let the library
  * compile). */
diff --git a/plat/rpi/include/unistd.h b/plat/rpi/include/unistd.h
index 6c220d10f..506d781ee 100644
--- a/plat/rpi/include/unistd.h
+++ b/plat/rpi/include/unistd.h
@@ -67,6 +67,7 @@ extern int open(const char* path, int access, ...);
 extern int creat(const char* path, mode_t mode);
 extern int read(int fd, void* buffer, size_t count);
 extern int write(int fd, void* buffer, size_t count);
+extern int unlink(const char* path);
 
 /* Unimplemented system calls (these are just prototypes to let the library
  * compile). */