Provide fallback definitions of PRIu32 and PRIx32

Since 6e1c23442 we make use of these C99 constructs, but this commit did
not provide fallbacks for non-C99 systems.

Signed-off-by: Johannes Sixt <johannes.sixt@telecom.at>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-compat-util.h

@@ -110,6 +110,14 @@
 #define PRIuMAX "llu"
 #endif
 
+#ifndef PRIu32
+#define PRIu32 "u"
+#endif
+
+#ifndef PRIx32
+#define PRIx32 "x"
+#endif
+
 #ifndef PATH_SEP
 #define PATH_SEP ':'
 #endif