> The only other way I see is to have a global core_evalUrl variable and require anyone who wants to override the ajax module to do a custom build.

It's not practical. One would be expected to have a build without ajax and be able to use this build with whatever third party ajax lib (or none: `$._evalURL = $.noop;`) they see fit, not have to rebuild a custom version per third-party. Having to override a variable in the closure at build time is overkill when a private overridable hook on the `jQuery` object does the job perfectly.

I understand rick's reservations with this but I don't think we can offer a practical solution any other way. We can build jQuery without ajax now, so we should provide this hook.