Updated version of RISCOS support. SF patch 411213 by Dietmar Schwertberger

Python/sysmodule.c

@@ -808,7 +808,11 @@ PySys_SetArgv(int argc, char **argv)
 		if (argc > 0 && argv0 != NULL)
 			p = strrchr(argv0, SEP);
 		if (p != NULL) {
+#ifndef RISCOS
 			n = p + 1 - argv0;
+#else /* don't include trailing separator */
+			n = p - argv0;
+#endif /* RISCOS */
 #if SEP == '/' /* Special case for Unix filename syntax */
 			if (n > 1)
 				n--; /* Drop trailing separator */