[libxml2] Fix a portability issue for GCC < 3.4.0

[Daniel Veillard <veillard src gnome org>]

commit 4ea74a440d6f7ff0f6e2d25a780aee21f86762a8
Author: Daniel Veillard <veillard redhat com>
Date:   Mon Oct 29 10:27:18 2012 +0800

    Fix a portability issue for GCC < 3.4.0

 timsort.h |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/timsort.h b/timsort.h
index b3a32f0..99697a0 100644
--- a/timsort.h
+++ b/timsort.h
@@ -48,7 +48,7 @@ typedef unsigned __int64 uint64_t;
 int compute_minrun(uint64_t);
 
 #ifndef CLZ
-#ifdef __GNUC__
+#if defined(__GNUC__) && ((__GNUC__ == 3 && __GNUC_MINOR__ >= 4) || (__GNUC__ > 3))
 #define CLZ __builtin_clzll
 #else