diff -ur bison-1.28.orig/src/files.c bison-1.28/src/files.c
--- bison-1.28.orig/src/files.c	Wed May 19 15:43:04 1999
+++ bison-1.28/src/files.c	Wed Jan  3 09:06:44 2001
@@ -42,6 +42,7 @@
 #endif
 
 #include <stdio.h>
+#include <stdlib.h>
 
 #ifdef HAVE_UNISTD_H
 #include <unistd.h>
@@ -76,15 +77,12 @@
 
 extern int noparserflag;
 
-extern char	*mktemp();	/* So the compiler won't complain */
-extern char	*getenv();
-extern void	perror();
-
 char *stringappend PARAMS((char *, int, char *));
 void openfiles PARAMS((void));
 void open_extra_files PARAMS((void));
 FILE *tryopen PARAMS((char *, char *));	/* This might be a good idea */
 int tryclose PARAMS((FILE *));
+FILE *trytemp PARAMS((char *));
 void done PARAMS((int));
 
 extern char *program_name;
@@ -274,13 +272,6 @@
   tmpattrsfile = mktemp(stringappend(tmp_base, tmp_len, "atXXXXXX"));
   tmptabfile = mktemp(stringappend(tmp_base, tmp_len, "taXXXXXX"));
   tmpdefsfile = mktemp(stringappend(tmp_base, tmp_len, "deXXXXXX"));
-#else
-  if (! noparserflag)
-    actfile = mktemp(stringappend(tmp_base, tmp_len, "act.XXXXXX"));
-  tmpattrsfile = mktemp(stringappend(tmp_base, tmp_len, "attrs.XXXXXX"));
-  tmptabfile = mktemp(stringappend(tmp_base, tmp_len, "tab.XXXXXX"));
-  tmpdefsfile = mktemp(stringappend(tmp_base, tmp_len, "defs.XXXXXX"));
-#endif /* not MSDOS */
 
   if (! noparserflag)
     faction = tryopen(actfile, "w+");
@@ -292,13 +283,25 @@
       defsfile = stringappend(name_base, base_length, ".h");
       fdefines = tryopen(tmpdefsfile, "w+");
     }
+#else
+  if (! noparserflag)
+    faction = trytemp(actfile = stringappend(tmp_base, tmp_len, "act.XXXXXX"));
+  fattrs = trytemp(tmpattrsfile = stringappend(tmp_base, tmp_len, "attrs.XXXXXX"));
+  ftable = trytemp(tmptabfile = stringappend(tmp_base, tmp_len, "tab.XXXXXX"));
+  if (definesflag)
+    {
+      defsfile = stringappend(name_base, base_length, ".h");
+      fdefines = trytemp(tmpdefsfile = stringappend(tmp_base, tmp_len, "defs.XXXXXX"));
+    }
+#endif /* not MSDOS */
 
 #if !(defined (MSDOS) || (defined(_WIN32) && !defined(__CYGWIN32__)))
   if (! noparserflag)
     unlink(actfile);
   unlink(tmpattrsfile);
   unlink(tmptabfile);
-  unlink(tmpdefsfile);
+  if (definesflag)
+    unlink(tmpdefsfile);
 #endif /* MSDOS || (_WIN32 && !__CYGWIN32__) */
 
 	/* These are opened by `done' or `open_extra_files', if at all */
@@ -401,6 +404,22 @@
       done (2);
     }
   return result;
+}
+
+FILE *
+trytemp (char *template)
+{
+  int fd;
+  FILE *ptr;
+
+  if ((fd = mkstemp(template)) == -1 || (ptr = fdopen(fd, "r+")) == NULL)
+    {
+      fprintf(stderr, "%s: ", program_name);
+      perror("mkstemp");
+      if (fd != -1) unlink(template);
+      done(2);
+    }
+  return ptr;
 }
 
 void