diff --git a/fcc/driver/fcc.c b/fcc/driver/fcc.c
index 6421f9067..101fa3fce 100644
--- a/fcc/driver/fcc.c
+++ b/fcc/driver/fcc.c
@@ -21,9 +21,14 @@
 
 #include <errno.h>
 #include <signal.h>
-#include <varargs.h>
 #include <stdio.h>
 #include <em_path.h>
+#if __STDC__
+#include <stdarg.h>
+#else
+#include <varargs.h>
+#endif
+
 
 /*
 	Version producing cc-compatible .o files in one pass.
@@ -117,7 +122,11 @@ int c_flag = 0;
 int v_flag = 0;
 int O_flag = 0;
 
+#if __STDC__
+char *mkstr(char *, ...);
+#else
 char *mkstr();
+#endif
 char *malloc();
 char *alloc();
 char *extension();
@@ -483,6 +492,32 @@ concat(al1, al2)
 	}
 }
 
+#if __STDC__
+/*VARARGS*/
+char *
+mkstr(char *dst, ...)
+{
+	va_list ap;
+
+	va_start(ap, dst);
+	{
+		register char *p;
+		register char *q;
+
+		q = dst;
+		p = va_arg(ap, char *);
+
+		while (p) {
+			while (*q++ = *p++);
+			q--;
+			p = va_arg(ap, char *);
+		}
+	}
+	va_end(ap);
+
+	return dst;
+}
+#else
 /*VARARGS*/
 char *
 mkstr(va_alist)
@@ -509,6 +544,7 @@ mkstr(va_alist)
 
 	return dst;
 }
+#endif
 
 basename(str, dst)
 	char *str;
diff --git a/util/ceg/EM_parser/common/help.c b/util/ceg/EM_parser/common/help.c
index 85a54a0d0..a997354bb 100644
--- a/util/ceg/EM_parser/common/help.c
+++ b/util/ceg/EM_parser/common/help.c
@@ -1,6 +1,11 @@
 #include <ctype.h>
 #include <system.h>
+#if __STDC__
+#include <stdarg.h>
+extern out(char *, ...);
+#else
 #include <varargs.h>
+#endif
 
 #define CODE_EXPANDER
 #include "em.h"
@@ -99,6 +104,17 @@ int seg;
 	}
 }
 
+#if __STDC__
+/*VARARGS*/
+out(char *fmt, ...)
+{
+        va_list pvar;
+ 
+        va_start(pvar, fmt);
+        doprnt( outfile, fmt, pvar);
+        va_end(pvar);
+}
+#else
 /*VARARGS*/
 out(va_alist)
 va_dcl
@@ -111,6 +127,7 @@ va_dcl
         doprnt( outfile, fmt, pvar);
         va_end(pvar);
 }
+#endif
 
 char *suffix( str, suf)
 char *str, *suf;
diff --git a/util/ceg/as_parser/help.c b/util/ceg/as_parser/help.c
index 4fb4b608e..4f3575018 100644
--- a/util/ceg/as_parser/help.c
+++ b/util/ceg/as_parser/help.c
@@ -1,4 +1,10 @@
-#include "varargs.h"
+#if __STDC__
+#include <stdarg.h>
+extern out(char *, ...);
+extern error(char *, ...);
+#else
+#include <varargs.h>
+#endif
 #include "decl.h"
 
 /* All the functions in this file will be called by the parser.
@@ -208,6 +214,32 @@ operand_clean()
 	n_ops = 0;
 }
 
+#if __STDC__
+/*VARARGS*/
+out(char *fmt, ...)
+{
+	va_list pvar;
+
+	va_start(pvar, fmt);
+	doprnt( outfile, fmt, pvar);
+	va_end(pvar);
+}
+
+extern int nerrors;
+
+/*VARARGS*/
+error(char *fmt, ...)
+{
+	va_list pvar;
+
+	nerrors++;
+	va_start(pvar, fmt);
+	fprint( STDERR, "!! ERROR :	");
+	doprnt( STDERR, fmt, pvar);
+	fprint( STDERR, "	!!\n");
+	va_end(pvar);
+}
+#else
 /*VARARGS*/
 out(va_alist)
 va_dcl
@@ -238,6 +270,7 @@ va_dcl
 	fprint( STDERR, "	!!\n");
 	va_end(pvar);
 }
+#endif
 
 inc_ops()
 {
diff --git a/util/ceg/assemble/obj_assemble/assemble.c b/util/ceg/assemble/obj_assemble/assemble.c
index f5113e1c4..abd801798 100644
--- a/util/ceg/assemble/obj_assemble/assemble.c
+++ b/util/ceg/assemble/obj_assemble/assemble.c
@@ -1,7 +1,12 @@
 #include <ctype.h>
 #include <system.h>
 #include <stdio.h>
+#if __STDC__
+#include <stdarg.h>
+extern error(char *, ...);
+#else
 #include <varargs.h>
+#endif
 #include "as.h"
 #include "const.h"
 
@@ -224,6 +229,22 @@ char *mnem;
 
 /*** Error ****************************************************************/
 
+#if __STDC__
+/*VARARGS*/
+error(char *fmt, ...)
+{
+	va_list args;
+	extern int yylineno;
+	extern int nerrors;
+
+	va_start(args, fmt);
+		fprint( STDERR, "ERROR in line %d :	", yylineno);
+		doprnt( STDERR, fmt, args);
+		fprint( STDERR, "\n");
+	va_end(args);
+	nerrors++;
+}
+#else
 /*VARARGS*/
 error(va_alist)
 	va_dcl
@@ -241,3 +262,4 @@ error(va_alist)
 	va_end(args);
 	nerrors++;
 }
+#endif
diff --git a/util/ceg/ce_back/obj_back/extnd.c b/util/ceg/ce_back/obj_back/extnd.c
index 2fda33b83..e367d0faf 100644
--- a/util/ceg/ce_back/obj_back/extnd.c
+++ b/util/ceg/ce_back/obj_back/extnd.c
@@ -4,7 +4,11 @@
 #include "header.h"
 #include "back.h"
 #include "mach.h"
+#if __STDC__
+#include <stdarg.h>
+#else
 #include <varargs.h>
+#endif
 
 /* Mysprint() stores the string directly in the string_arae. This saves
  * a copy action. It is assumed that the strings stored in the string-table
@@ -13,6 +17,22 @@
 
 #define MAXSTRLEN	1024
 
+#if __STDC__
+/*VARARGS*/
+static int mysprint(char *fmt, ...)
+{
+	va_list args;
+	int retval;
+
+	va_start(args, fmt);
+	while (string + MAXSTRLEN - string_area > size_string)
+		mem_string();
+	retval = _format(string, fmt, args);
+	string[retval] = '\0';
+	va_end(args);
+	return retval;
+}
+#else
 /*VARARGS*/
 static int mysprint(va_alist)
 	va_dcl
@@ -30,6 +50,7 @@ static int mysprint(va_alist)
 	va_end(args);
 	return retval;
 }
+#endif
 
 /* The extnd_*()s make a name unique. The resulting string is directly stored
  * in the symbol_table (by mysprint()). Later additional fields in the