Changing constant in src/include/miscadmin.h

Hello!

Is it valid to change a constant in src/include/miscadmin.h?

===========================
@@ -150,10 +150,10 @@

 #define MAXTZLEN               10              /* max TZ name len, not counting tr. null */

-#define USE_POSTGRES_DATES             0
 #define USE_ISO_DATES                  1
 #define USE_SQL_DATES                  2
 #define USE_GERMAN_DATES               3
+#define USE_POSTGRES_DATES             4

 extern int     DateStyle;
 extern bool EuroDates;
===========================

This can make easy parsing of date style in parse_datestyle_internal
function (src/backend/commands/variable.c) in this way:

datestyle=0;
if () datestyle=USE_xxx
...
if (!datestyle) elog(ERROR

-- 
WBR, Yury Bokhoncovich, Senior System Administrator, NOC of F1 Group.
Phone: +7 (3832) 106228, ext.140, E-mail: byg@center-f1.ru.
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