X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/561f9a30af99cfbd4dbb51bcc82506c987cb92a9..270a173cf307c5032f3644593eef0d66ed68676f:/src/files.c

diff --git a/src/files.c b/src/files.c
index 7e29c4c6..0dbcac37 100644
--- a/src/files.c
+++ b/src/files.c
@@ -86,26 +86,36 @@ stringappend (const char *string1, const char *string2)
 }
 
 
-/*---------------------------------------------------------------.
-|  Computes the macro name used to avoid double inclusion in the |
-|  header of the parser and store it in header_macro_name.       |
-`---------------------------------------------------------------*/
+/*-----------------------------------------------------------------.
+| Computes the macro name used to avoid double inclusion in the    |
+| header of the parser and store it in header_macro_name.  Be sure |
+| to produce valid CPP names (don't start with digit, remain       |
+| alphanumerical + underscore).                                    |
+`-----------------------------------------------------------------*/
 
 static char *
 compute_header_macro (void)
 {
+  const char *prefix = "BISON_";
   char *macro_name, *cp;
 
   if (spec_defines_file)
-    macro_name = xstrdup (spec_defines_file);
+    {
+      macro_name = XMALLOC (char,
+			    strlen (prefix) +
+			    strlen (spec_defines_file) + 1);
+      cp = stpcpy (macro_name, prefix);
+      cp = stpcpy (cp, spec_defines_file);
+    }
   else
     {
       macro_name = XMALLOC (char,
+			    strlen (prefix) +
 			    strlen (base_name) +
 			    strlen (header_extension) + 1);
-
-      stpcpy (macro_name, base_name);
-      strcat (macro_name, header_extension);
+      cp = stpcpy (macro_name, prefix);
+      cp = stpcpy (cp, base_name);
+      cp = stpcpy (cp, header_extension);
     }
 
   for (cp = macro_name; *cp; ++cp)