Patch #734231: Update RiscOS support. In particular, correct
riscospath.extsep, and use os.extsep throughout.
diff --git a/Modules/zipimport.c b/Modules/zipimport.c
index 9f7da72..f0eaef5 100644
--- a/Modules/zipimport.c
+++ b/Modules/zipimport.c
@@ -91,6 +91,7 @@
 	path = NULL;
 	prefix = NULL;
 	for (;;) {
+#ifndef RISCOS
 		struct stat statbuf;
 		int rv;
 
@@ -102,6 +103,15 @@
 				path = buf;
 			break;
 		}
+#else
+		if (object_exists(buf)) {
+			/* it exists */
+			if (isfile(buf))
+				/* it's a file */
+				path = buf;
+			break;
+		}
+#endif
 		/* back up one path element */
 		p = strrchr(buf, SEP);
 		if (prefix != NULL)