Define bool as unsigned char (1 byte) on old MSVC versions

include/ua_config.h.in

@@ -75,7 +75,7 @@ extern "C" {
 #else
 # include "ms_stdint.h"
 # if !defined(__bool_true_false_are_defined)
-#  define bool short
+#  define bool unsigned char
 #  define true 1
 #  define false 0
 #  define __bool_true_false_are_defined