New substitution variable BUILD_LIBMYSQL.

Append linker flags to AUTHLIBS, since modifying LIBS effectively
breaks compilation.

@@ -130,12 +130,15 @@ if test x"$ac_cv_func_argp_parse" != xyes; then
 fi
 
 dnl check if mysql support was added
+AC_SUBST(BUILD_LIBMYSQL)
+AC_SUBST(MYSQLLIBS)
 AC_ARG_ENABLE(mysql, [  --enable-mysql  enable mysql support (default no)], [use_mysql="yes"],,)
 if test x"$use_mysql" = x"yes"; then
 	echo Enabling mysql support, be sure to edit \'MySql/MySql.h\' to change default values
 	AC_CHECK_HEADER(mysql/mysql.h,
-	LIBS="$LIBS -lmailMysql -lmysqlclient -L/usr/lib/mysql -L/usr/local/lib/mysql -L../MySql/"
-	AC_DEFINE(HAVE_MYSQL))
+	[AUTHLIBS="$AUTHLIBS -lmailMysql -lmysqlclient -L/usr/lib/mysql -L/usr/local/lib/mysql -L../MySql/"
+        BUILD_LIBMYSQL=libmailMysql.a
+	AC_DEFINE(HAVE_MYSQL)])
 fi
 
 dnl Virtual domain support, at least for pop3d