* allow configuration of mysql version

svn path=/nixos/trunk/; revision=18993

modules/services/databases/mysql.nix

@@ -6,7 +6,7 @@ let
 
   cfg = config.services.mysql;
 
-  mysql = pkgs.mysql;
+  mysql = cfg.mysql;
 
   pidFile = "${cfg.pidDir}/mysqld.pid";
 
@@ -31,6 +31,13 @@ in
         ";
       };
 
+      mysql = mkOption {
+        default = pkgs.mysql;
+        description = "
+          Which MySQL derivation to use.
+        ";
+      };
+
       port = mkOption {
         default = "3306";
         description = "Port of MySQL";