Improve win32 link test. Previous commit added most of the code, but

this commit enables only for Mingw.

configure.in

 dnl Process this file with autoconf to produce a configure script.
-dnl $PostgreSQL: pgsql/configure.in,v 1.350 2004/05/18 04:10:30 momjian Exp $
+dnl $PostgreSQL: pgsql/configure.in,v 1.351 2004/05/18 04:11:29 momjian Exp $
 dnl
 dnl Developers, please strive to achieve this order:
 dnl
@@ -1236,8 +1236,7 @@ AC_CONFIG_LINKS([
   src/Makefile.port:src/makefiles/Makefile.${template}
 ])
 
-case $host_os in mingw*);;
-*)
+case $host_os in mingw*)
 AC_CONFIG_COMMANDS([check_win32_symlinks],[
 # Links sometimes fail undetected on Mingw - 
 # so here we detect it and warn the user