Index: string_primitives.c
===================================================================
--- string_primitives.c	(revision 26507)
+++ string_primitives.c	(working copy)
@@ -314,7 +314,7 @@
 #else
     if ((character >= 0x30) || (character <= 0x39))
         return character - 0x30;
-    return -1;
+    return ((UINTVAL)-1);
 #endif
 }