Fix minor WIN32 incompatibility

File mode flags are not all defined on WIN32, but since git
is so rigid in how it uses file modes, there is no reason not
to hard code a particular value.  Also, this is only used in
the git_diff_print_compact helper function, so it is really
really not important.

src/diff.c

@@ -445,7 +445,10 @@ static char pick_suffix(int mode)
 {
 	if (S_ISDIR(mode))
 		return '/';
-	else if (mode & S_IXUSR)
+	else if (mode & 0100)
+		/* modes in git are not very flexible, so if this bit is set,
+		 * we must be dealwith with a 100755 type of file.
+		 */
 		return '*';
 	else
 		return ' ';