range.h: Define typeof with __typeof__

Depending on toolchains, "typeof" is used instead of "__typeof__".
This is to avoid a compile error caused by missing "typeof".

Signed-off-by: Younghyun Park <younghyunpark@google.com>
Change-Id: I9c224151cee32fdb71e1caefb25ea53cc475ff42
diff --git a/range.h b/range.h
index 7b1f010..20349f2 100644
--- a/range.h
+++ b/range.h
@@ -1,6 +1,10 @@
 #ifndef _RANGE_H
 #define _RANGE_H
 
+#ifndef typeof
+#define typeof __typeof__
+#endif
+
 #ifndef MIN
 #define MIN(a, b)                                                              \
 	({                                                                     \