Add support for external spec file via the GNAT_SPECS env var.  This
	allows us to easily control compiler spec defaults.

	Original patch for gcc by Rob Holland.  Extended to support multiple
	entries separated by ':' and adjusted for gnat builds by Kevin F. Quinn

--- gnat-3/gcc/gcc.c.orig	2005-12-04 18:38:28.000000000 +0100
+++ gnat-3/gcc/gcc.c	2005-12-04 18:44:33.000000000 +0100
@@ -6482,6 +6482,30 @@
 
   /* Process any user specified specs in the order given on the command
      line.  */
+  /* Add specs listed in GNAT_SPECS.  Note; in the process of separating
+   * each spec listed, the string is overwritten at token boundaries
+   * with '\0', an effect of strtok_r().
+   */
+  GET_ENVIRONMENT (specs_file, "GNAT_SPECS");
+  if (specs_file && (strlen(specs_file) > 0))
+    {
+      char *spec, *saveptr;
+      for (spec=strtok_r(specs_file,":",&saveptr);
+           spec!=NULL;
+           spec=strtok_r(NULL,":",&saveptr))
+        {
+          struct user_specs *user = (struct user_specs *)
+            xmalloc (sizeof (struct user_specs));
+
+          user->next = (struct user_specs *) 0;
+          user->filename = spec;
+          if (user_specs_tail)
+            user_specs_tail->next = user;
+          else
+            user_specs_head = user;
+          user_specs_tail = user;
+        }
+    }
   for (uptr = user_specs_head; uptr; uptr = uptr->next)
     {
       char *filename = find_a_file (&startfile_prefixes, uptr->filename,