diff --git a/h/con_float b/h/con_float
index 903c2ce5b..b2ad2908b 100644
--- a/h/con_float
+++ b/h/con_float
@@ -237,6 +237,7 @@ float_cst(str, sz, buf)
 #endif /* USE_FLT */
 
 #ifdef CODE_GENERATOR
+void
 con_float()
 {
 	char buf[8];
diff --git a/mach/i386/ncg/mach.c b/mach/i386/ncg/mach.c
index 7514d6775..1497974be 100644
--- a/mach/i386/ncg/mach.c
+++ b/mach/i386/ncg/mach.c
@@ -15,6 +15,7 @@ static char rcs_mh[]= ID_MH ;
  * machine dependent back end routines for the Intel 80386
  */
 
+void
 con_part(sz,w) register sz; word w; {
 
 	while (part_size % sz)
@@ -32,6 +33,7 @@ con_part(sz,w) register sz; word w; {
 	part_size += sz;
 }
 
+void
 con_mult(sz) word sz; {
 	long l;
 
@@ -92,6 +94,7 @@ long si_off;
 long di_off;
 int firstreg;
 
+int
 regscore(off, size, typ, score, totyp)
 	long off;
 {
@@ -104,6 +107,7 @@ regscore(off, size, typ, score, totyp)
 	return score;
 }
 
+void
 i_regsave()
 {
 	si_off = -1;
@@ -111,6 +115,7 @@ i_regsave()
 	firstreg = 0;
 }
 
+void
 f_regsave()
 {
 	if (si_off != di_off) {
@@ -133,6 +138,7 @@ f_regsave()
 		fprintf(codefile, "mov edi,%ld(ebp)\n", di_off);
 }
 
+void
 regsave(regstr, off, size)
 	char *regstr;
 	long off;
@@ -147,6 +153,7 @@ regsave(regstr, off, size)
 	}
 }
 
+void
 regreturn()
 {
 	if (firstreg == 1) {
@@ -165,6 +172,7 @@ regreturn()
 static int gdb_flag = 0;
 static char *fp_hook_nam;
 
+void
 mach_option(s)
 	char *s;
 {
diff --git a/mach/i80/ncg/mach.c b/mach/i80/ncg/mach.c
index 9f952f0d9..89d7b0149 100644
--- a/mach/i80/ncg/mach.c
+++ b/mach/i80/ncg/mach.c
@@ -12,6 +12,9 @@ static char rcsid[]=	"$Id$" ;
  * machine dependent back end routines for the Intel 8080.
  */
 
+#include <stdlib.h> /* atol */
+
+void
 con_part(sz,w) register sz; word w; {
 
 	while (part_size % sz)
@@ -30,8 +33,7 @@ con_part(sz,w) register sz; word w; {
 	part_size += sz;
 }
 
-long atol();
-
+void
 con_mult(sz) word sz; {
 
 	if (argval != 4)
@@ -39,6 +41,7 @@ con_mult(sz) word sz; {
 	fprintf(codefile,".data4\t%ld\n",atol(str));
 }
 
+void
 con_float() {
 	static int warning_given;
 	int i = argval;
diff --git a/mach/i86/ncg/mach.c b/mach/i86/ncg/mach.c
index a305d6d9a..817599147 100644
--- a/mach/i86/ncg/mach.c
+++ b/mach/i86/ncg/mach.c
@@ -13,6 +13,7 @@ static char rcs_mh[]= ID_MH ;
  * machine dependent back end routines for the Intel 8086
  */
 
+void
 con_part(sz,w) register sz; word w; {
 
 	while (part_size % sz)
@@ -31,6 +32,7 @@ con_part(sz,w) register sz; word w; {
 	part_size += sz;
 }
 
+void
 con_mult(sz) word sz; {
 	long l;
 
@@ -83,6 +85,7 @@ long si_off;
 long di_off;
 int firstreg;
 
+int
 regscore(off, size, typ, score, totyp)
 	long off;
 {
@@ -95,6 +98,7 @@ regscore(off, size, typ, score, totyp)
 	return score;
 }
 
+void
 i_regsave()
 {
 	si_off = -1;
@@ -102,6 +106,7 @@ i_regsave()
 	firstreg = 0;
 }
 
+void
 f_regsave()
 {
 	if (si_off != di_off) {
@@ -130,6 +135,7 @@ f_regsave()
 		fprintf(codefile, "mov si,%ld(bp)\n", si_off);
 }
 
+void
 regsave(regstr, off, size)
 	char *regstr;
 	long off;
@@ -144,6 +150,7 @@ regsave(regstr, off, size)
 	}
 }
 
+void
 regreturn()
 {
 	if (firstreg == 1) {
diff --git a/mach/m68020/ncg/mach.c b/mach/m68020/ncg/mach.c
index 915b4f6e2..4f710348d 100644
--- a/mach/m68020/ncg/mach.c
+++ b/mach/m68020/ncg/mach.c
@@ -17,6 +17,7 @@
 
 #include <stb.h>
 
+void
 con_part(sz,w) register sz; word w; {
 
 	while (part_size % sz)
@@ -43,6 +44,7 @@ con_part(sz,w) register sz; word w; {
 	part_size += sz;
 }
 
+void
 con_mult(sz) word sz; {
 
 	if (sz != 4)
@@ -57,6 +59,7 @@ con_mult(sz) word sz; {
 #define FL_MSB_AT_LOW_ADDRESS	1
 #include <con_float>
 
+int
 regscore(off,size,typ,score,totyp)
 	long off;
 {
@@ -93,6 +96,7 @@ struct regsav_t {
 
 int regnr;
 
+void
 i_regsave()
 {
 	regnr = 0;
@@ -100,6 +104,7 @@ i_regsave()
 
 full nlocals;
 
+void
 regreturn()
 {
 	register struct regsav_t *p;
@@ -127,6 +132,7 @@ regreturn()
 	fputs("unlk a6\nrts\n", codefile);
 }
 
+void
 f_regsave()
 {
 	register struct regsav_t *p;
@@ -176,6 +182,7 @@ f_regsave()
 	}
 }
 
+void
 regsave(s,off,size)
 	char *s;
 	long off;
@@ -196,6 +203,7 @@ prolog(n) full n; {
 #ifdef MACH_OPTIONS
 static int gdb_flag = 0;
 
+void
 mach_option(s)
 	char *s;
 {
diff --git a/mach/powerpc/ncg/mach.c b/mach/powerpc/ncg/mach.c
index 6e0eef98b..b67903b0a 100644
--- a/mach/powerpc/ncg/mach.c
+++ b/mach/powerpc/ncg/mach.c
@@ -13,6 +13,7 @@
 
 static long framesize;
 
+void
 con_part(int sz, word w)
 {
 	while (part_size % sz)
@@ -34,6 +35,7 @@ con_part(int sz, word w)
 	part_size += sz;
 }
 
+void
 con_mult(word sz)
 {
 
@@ -146,6 +148,7 @@ regscore(long offset, int size, int type, int frequency, int totype)
 
 /* Initialise regvar system for one function. */
 
+void
 i_regsave(void)
 {
 	int i;
@@ -163,6 +166,7 @@ i_regsave(void)
 
 /* Mark a register as being saved. */
 
+void
 regsave(const char* regname, long offset, int size)
 {
 	int regnum = atoi(regname + 1);
@@ -223,6 +227,7 @@ saveloadregs(const char* ops, const char* opm, const char *opf)
 	}
 }
 
+void
 f_regsave(void)
 {
 	int reg;
@@ -248,6 +253,7 @@ f_regsave(void)
 
 /* Restore all saved registers. */
 
+void
 regreturn(void)
 {
 	saveloadregs("lwz", "lmw", "lfd");
diff --git a/mach/proto/ncg/codegen.c b/mach/proto/ncg/codegen.c
index 7339265b7..3a2d60d1a 100644
--- a/mach/proto/ncg/codegen.c
+++ b/mach/proto/ncg/codegen.c
@@ -14,6 +14,9 @@ static char rcsid[] = "$Id$";
 #include "state.h"
 #include "equiv.h"
 #include "extern.h"
+#ifdef REGVARS
+#include "regvar.h" /* regreturn */
+#endif
 
 /*
  * (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
diff --git a/mach/proto/ncg/fillem.c b/mach/proto/ncg/fillem.c
index c9f3fb5b3..07e6c9331 100644
--- a/mach/proto/ncg/fillem.c
+++ b/mach/proto/ncg/fillem.c
@@ -81,6 +81,9 @@ extern char em_flag[];
 extern short em_ptyp[];
 
 /* machine dependent */
+void con_part(int, word);
+void con_mult(word);
+void con_float(void);
 void prolog(full nlocals);
 void mes(word);
 
diff --git a/mach/proto/ncg/regvar.h b/mach/proto/ncg/regvar.h
index 2f3bfecd0..06c3e1207 100644
--- a/mach/proto/ncg/regvar.h
+++ b/mach/proto/ncg/regvar.h
@@ -36,3 +36,10 @@ void unlinkregs(void);
 #else
 #define PICK_REGVAR(off, size) isregvar(off)
 #endif
+
+/* machine dependent */
+int regscore(long, int, int, int, int);
+void i_regsave(void);
+void regsave(const char *, long, int);
+void f_regsave(void);
+void regreturn(void);
diff --git a/mach/proto/ncg/types.h b/mach/proto/ncg/types.h
index 2f88bfbb6..35b848e82 100644
--- a/mach/proto/ncg/types.h
+++ b/mach/proto/ncg/types.h
@@ -66,3 +66,7 @@ void garbage_collect(void);
 void itokcost(void);
 void error(const char *s, ...);
 void fatal(const char *s, ...);
+
+#ifdef MACH_OPTIONS
+void mach_option(char *); /* machine dependent */
+#endif
diff --git a/mach/vc4/ncg/mach.c b/mach/vc4/ncg/mach.c
index 8832f744f..16ca94f35 100644
--- a/mach/vc4/ncg/mach.c
+++ b/mach/vc4/ncg/mach.c
@@ -12,7 +12,7 @@ int framesize;
 
 /* Write out a constant data section. */
 
-con_part(int sz, word w)
+void con_part(int sz, word w)
 {
 	while (part_size % sz)
 		part_size++;
@@ -29,7 +29,7 @@ con_part(int sz, word w)
 	part_size += sz;
 }
 
-con_mult(word sz)
+void con_mult(word sz)
 {
 	if (argval != 4)
 		fatal("bad icon/ucon size");
@@ -49,7 +49,7 @@ void prolog(full nlocals)
 	fprintf(codefile, "push fp, lr\n");
 	fprintf(codefile, "mov fp, sp\n");
 	if (nlocals > 0)
-		fprintf(codefile, "sub sp, #%d\n", nlocals);
+		fprintf(codefile, "sub sp, #%ld\n", nlocals);
 
 	framesize = nlocals;
 }