mac: on 32 bit, use __builtin_umull_overflow

Author: Edward Thomson

src/integer.h

@@ -55,16 +55,16 @@ GIT_INLINE(bool) git__add_uint64_overflow(uint64_t *out, uint64_t one, uint64_t
 }
 
 /* Use clang/gcc compiler intrinsics whenever possible */
-#if (SIZE_MAX == UINT_MAX) && __has_builtin(__builtin_uadd_overflow)
-# define git__add_sizet_overflow(out, one, two) \
-	__builtin_uadd_overflow(one, two, out)
-# define git__multiply_sizet_overflow(out, one, two) \
-	__builtin_umul_overflow(one, two, out)
-#elif (SIZE_MAX == ULONG_MAX) && __has_builtin(__builtin_uaddl_overflow)
+#if (SIZE_MAX == ULONG_MAX) && __has_builtin(__builtin_uaddl_overflow)
 # define git__add_sizet_overflow(out, one, two) \
 	__builtin_uaddl_overflow(one, two, out)
 # define git__multiply_sizet_overflow(out, one, two) \
 	__builtin_umull_overflow(one, two, out)
+#elif (SIZE_MAX == UINT_MAX) && __has_builtin(__builtin_uadd_overflow)
+# define git__add_sizet_overflow(out, one, two) \
+	__builtin_uadd_overflow(one, two, out)
+# define git__multiply_sizet_overflow(out, one, two) \
+	__builtin_umul_overflow(one, two, out)
 #else
 
 /**