librhash: Explicitly enable large file support on 32-bit targets

`_LARGEFILE_SOURCE` is needed at least on SunOS i386 if compiler
extensions are not enabled.

Utilities/cmlibrhash/librhash/rhash.c

@@ -20,6 +20,7 @@
 #endif
 
 /* macros for large file support, must be defined before any include file */
+#define _LARGEFILE_SOURCE
 #define _LARGEFILE64_SOURCE
 #define _FILE_OFFSET_BITS 64