[PATCH] Fix var declaration according scanf specification,

Hi,
According to specification of scanf: %x argument must be unsigned.
http://www.cplusplus.com/reference/cstdio/scanf/
I think that sscanf must follow scanf specification.

Best regards.
Ranier Vilela

--- \dll\postgresql\a\backend\utils\adt\mac.c    2019-11-23 13:19:20.000000000 -0300
+++ mac.c    2019-11-24 09:49:01.737639100 -0300
@@ -57,7 +57,7 @@
 {
     char       *str = PG_GETARG_CSTRING(0);
     macaddr    *result;
-    int            a,
+    unsigned int a,
                 b,
                 c,
                 d,