MDEV-4249 : when autodetecting default client charset on Windows, fallback to...

MDEV-4249 : when autodetecting default client charset on Windows, fallback to GetACP() whenever GetConsoleCP() returns 0 (i.e appkication does not have a console , which is the case for GUI apps, Windows services etc)

sql-common/client.c

@@ -2198,7 +2198,10 @@ mysql_autodetect_character_set(MYSQL *mysql)
 #ifdef __WIN__
   char cpbuf[64];
   {
-    my_snprintf(cpbuf, sizeof(cpbuf), "cp%d", (int) GetConsoleCP());
+    UINT cp= GetConsoleCP();
+    if (cp == 0)
+      cp= GetACP();
+    my_snprintf(cpbuf, sizeof(cpbuf), "cp%d", (int)cp);
     csname= my_os_charset_to_mysql_charset(cpbuf);
   }
 #elif defined(HAVE_SETLOCALE) && defined(HAVE_NL_LANGINFO)