[PATCH] Allow multiple modules with the same name to coexist in the module cache

[Argyrios Kyrtzidis]

> 
> What I'm suggesting is:
> 
> 1) Drop the -I paths that are earlier than the module in the header search path when building the module
> 2) Include the rest of the header search paths in the configuration hash for the module

This will prevent us from sharing system modules across projects, and, as Ben already mentioned, will result in an explosion of module files, even within the same project.
Even if we include the search paths in the module hash we will still need to re-lookup the module dependencies before loading the module, because a new module.map may have showed up somewhere in the search paths since the time we built the module; unless I’m missing something, I don’t see any benefit in including the header search paths in the hash.