[PATCH] git-compat-util.h: GCC deprecated message arg only in GCC 4.5+

["Aleajndro R Sedeño" <asedeno@google.com>]

From: Alejandro R. Sedeño <asedeno@mit.edu>

From: https://gcc.gnu.org/gcc-4.5/changes.html

> The deprecated attribute now takes an optional string argument, for
> example, __attribute__((deprecated("text string"))), that will be
> printed together with the deprecation warning.

While GCC 4.5 is already 12 years old, git checks for even older
versions in places. Let's not needlessly break older compilers when
a small and simple fix is readily available.

Signed-off-by: Alejandro R. Sedeño <asedeno@mit.edu>
Signed-off-by: Alejandro R Sedeño <asedeno@google.com>
---
 git-compat-util.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/git-compat-util.h b/git-compat-util.h
index b90b64718e..045b47f83a 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -189,9 +189,12 @@ struct strbuf;
 #define _NETBSD_SOURCE 1
 #define _SGI_SOURCE 1
 
-#if defined(__GNUC__)
+#if GIT_GNUC_PREREQ(4, 5)
 #define UNUSED __attribute__((unused)) \
 	__attribute__((deprecated ("parameter declared as UNUSED")))
+#elif defined(__GNUC__)
+#define UNUSED __attribute__((unused)) \
+	__attribute__((deprecated))
 #else
 #define UNUSED
 #endif
-- 
2.38.0.rc1.362.ged0d419d3c-goog