Fix mingw link check by using double-brackets.

configure

@@ -19278,7 +19278,7 @@ echo "$as_me: executing $ac_dest commands" >&6;}
 for FILE in $CONFIG_LINKS
  do
 	# test -e works for symlinks in the MinGW console
-	test -e `expr "$FILE" : '\(^:*\)'` || { echo "$as_me:$LINENO: WARNING: *** link for $FILE - please fix by hand" >&5
+	test -e `expr "$FILE" : '\([^:]*\)'` || { echo "$as_me:$LINENO: WARNING: *** link for $FILE - please fix by hand" >&5
 echo "$as_me: WARNING: *** link for $FILE - please fix by hand" >&2;}
  done
  ;;

configure.in

 dnl Process this file with autoconf to produce a configure script.
-dnl $PostgreSQL: pgsql/configure.in,v 1.361 2004/06/07 22:39:43 momjian Exp $
+dnl $PostgreSQL: pgsql/configure.in,v 1.362 2004/06/08 14:06:35 momjian Exp $
 dnl
 dnl Developers, please strive to achieve this order:
 dnl
@@ -1241,7 +1241,7 @@ AC_CONFIG_COMMANDS([check_win32_symlinks],[
 for FILE in $CONFIG_LINKS
  do
 	# test -e works for symlinks in the MinGW console
-	test -e `expr "$FILE" : '\(^:*\)'` || AC_MSG_WARN([*** link for $FILE - please fix by hand])
+	test -e `expr "$FILE" : '\([[^:]]*\)'` || AC_MSG_WARN([*** link for $FILE - please fix by hand])
  done
 ])
 	;;