Build Recursion

[Kethku]

It would be convenient to allow coqproject.sh to run make when configuring the project on dependencies if they have not been built.

[wilcoxjay]

This seems a little tricky to do in general, since we don't know anything about the dependency's build system. I guess one option would be to try calling make in that directory at configure time.

It would be better if we could instead inform coq_makefile of the dependency's Makefile, so that things would automatically get rebuilt.