[PATCH v2] ewah: fix building with gcc < 3.4.0

["Tom G. Christensen" <tgc@statsbiblioteket.dk>]

The __builtin_ctzll function was added in gcc 3.4.0.
This extends the check for gcc so that use of __builtin_ctzll is only
enabled if gcc >= 3.4.0.

Signed-off-by: Tom G. Christensen <tgc@statsbiblioteket.dk>
---
v2:
Add S-o-b

v1:
I noticed this on RHEL3 during 2.0.0rc phase but I see that the same
issue was noticed on Debian Sarge:
http://article.gmane.org/gmane.comp.version-control.git/255190
RHEL3 ships with gcc 3.2.3.

With this patch git can build on RHEL3 provided cURL support is disabled.

 ewah/ewok.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/ewah/ewok.h b/ewah/ewok.h
index f6ad190..13c6e20 100644
--- a/ewah/ewok.h
+++ b/ewah/ewok.h
@@ -47,7 +47,8 @@ static inline uint32_t ewah_bit_popcount64(uint64_t x)
 	return (x * 0x0101010101010101ULL) >> 56;
 }
 
-#ifdef __GNUC__
+/* __builtin_ctzll was not available until 3.4.0 */
+#if defined(__GNUC__) && (__GNUC__ > 3 || (__GNUC__ == 3  && __GNUC_MINOR > 3))
 #define ewah_bit_ctz64(x) __builtin_ctzll(x)
 #else
 static inline int ewah_bit_ctz64(uint64_t x)
-- 
2.2.2