This is a spin-off of my current patch queue from bug 584474, to separate in two parts: one for the improvement of the fakelibs functionality (this bug), one for the avoidance of building intermediate libraries (bug 584474). The reason I'm going this way is that problems arose on current m-c when avoiding to build intermediate libraries (more specifically, OSX debug builds get broken), and while fixing these issues, I still want the fakelibs improvements to go in ; so to keep bug status clear, I figured creating a new bug would be better.

This bug is now useless. It turns out I found a way to avoid the OSX problems before I solved the problems I ran into when trying to get a patch queue for this bug. We can thus go directly with bug 584474.