diff --git a/mach/proto/top/top.c b/mach/proto/top/top.c
index 8964750d8..e44580af9 100644
--- a/mach/proto/top/top.c
+++ b/mach/proto/top/top.c
@@ -3,21 +3,24 @@
  * (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
  * See the copyright notice in the ACK home directory, in the file "Copyright".
  */
+ 
+#include <stdlib.h>
 #include <stdio.h>
+#include <string.h>
 #include "gen.h"
 #include "top.h"
 #include "queue.h"
 
+/* Defined in the string module, which has no header file. FIXME. */
+
+extern char* strindex(char *s, int c);
+
 /* STANDARD MACHINE-INDEPENT C CODE *************/
 
 extern char *lstrip();
 extern instr_p newinstr();
 extern instr_p read_instr();
 extern instr_p gen_instr();
-extern char * malloc();
-extern char *strcat();
-extern char *strcpy();
-extern char *strncpy();
 
 struct variable var[NRVARS+1];
 struct variable ANY;  /* ANY symbol matching any instruction */
diff --git a/util/topgen/hash.c b/util/topgen/hash.c
index b94501e61..7661dd375 100644
--- a/util/topgen/hash.c
+++ b/util/topgen/hash.c
@@ -8,8 +8,10 @@
  * maintains the the lists of hashed patterns
  * Functions : addtohashtable() and printhashtable()
  */
-# include <stdio.h>
-# include "misc.h"
+ 
+#include <stdlib.h>
+#include <stdio.h>
+#include "misc.h"
 
 struct hlist {			/* linear list of pattern numbers */
     int	h_patno;
@@ -40,7 +42,6 @@ addtohashtable(s,n) char *s; {
      */
     unsigned hval;
     register struct hlist *p;
-    char *malloc();
 
     hval = hash(s);
     p = (struct hlist *) malloc(sizeof *p);
diff --git a/util/topgen/main.c b/util/topgen/main.c
index 128730daf..dd6c4c8a2 100644
--- a/util/topgen/main.c
+++ b/util/topgen/main.c
@@ -8,7 +8,9 @@
  * Contains the main program, the error reporting routine, and a routine
  * to check wether a constraint consists only of space
  */
-# include <stdio.h>
+ 
+#include <stdlib.h>
+#include <stdio.h>
 
 extern int lineno, newline;
 
diff --git a/util/topgen/pattern.c b/util/topgen/pattern.c
index 5ae700817..bc5b7a64f 100644
--- a/util/topgen/pattern.c
+++ b/util/topgen/pattern.c
@@ -9,10 +9,12 @@
  * it maintains a table of information about the patterns
  * Functions : addpattern() and printpatterns()
  */
-# include <stdio.h>
-# include <ctype.h>
-# include "misc.h"
-# include "symtab.h"
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <ctype.h>
+#include "misc.h"
+#include "symtab.h"
 
 struct pattern {
     char *p_constraint;			/* constraint of this pattern */
@@ -37,7 +39,6 @@ addpattern(str,l,np,nr) char *str; {
      * "nr" is the number of instructions in the replacement
      * Space is allocated in chunks of 50
      */
-    char *malloc(), *realloc();
     register struct pattern *p;
 
     if (!pattable) {		/* No space allocated yet */
diff --git a/util/topgen/symtab.c b/util/topgen/symtab.c
index 05b1ed326..b5511d0dc 100644
--- a/util/topgen/symtab.c
+++ b/util/topgen/symtab.c
@@ -8,7 +8,10 @@
  * Contains the routine findident, which builds the symbol table and
  * searches identifiers
  */
-# include "symtab.h"
+ 
+#include <stdlib.h>
+#include <string.h>
+#include "symtab.h"
 
 struct symtab *idtable, *deftable;
 
@@ -20,8 +23,6 @@ findident(s, mode, table) char *s; struct symtab **table; {
      * If mode = ENTERING, a new entry will be made if s is not in the
      * table yet, otherwise an error results
      */
-    char *malloc();
-    char *strcpy();
     register struct symtab *p;
     register n;
 
diff --git a/util/topgen/topgen.g b/util/topgen/topgen.g
index cd187aee6..45c573e94 100644
--- a/util/topgen/topgen.g
+++ b/util/topgen/topgen.g
@@ -15,16 +15,16 @@
 %start	LLparse, optim_description;
 
 {
-# include <stdio.h>
-# include "token.h"
-# include "symtab.h"
-# include "misc.h"
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include "token.h"
+#include "symtab.h"
+#include "misc.h"
 
 char	idbuf[BUFSIZ], buf[BUFSIZ];
 int	countid;		/* # of variables */
 int	countpat;		/* # of patterns */
-char *	malloc();
-char *	strcpy();
 static int patlen;		/* Maximum number of instructions in pattern */
 static int maxoperand;		/* Maximum number of operands of instruction */
 extern FILE *input;		/* file descriptor of inputfile */