Sigh. The hack to enable special treatment for errno on SGI machines

must be enabled here, otherwise the errno we set on overflows is not
the errno that's being read by compile.c.  Wonder how many other files
that do their own "#include config.h" need this too :-(

(Because of the structure of autoconf, it's not so simple to get this
into config.h...)

Python/mystrtoul.c

@@ -31,6 +31,10 @@ PERFORMANCE OF THIS SOFTWARE.
 
 #include "config.h"
 
+#if defined(__sgi) && defined(WITH_THREAD) && !defined(_SGI_MP_SOURCE)
+#define _SGI_MP_SOURCE
+#endif
+
 /* Convert a possibly signed character to a nonnegative int */
 /* XXX This assumes characters are 8 bits wide */
 #ifdef __CHAR_UNSIGNED__