It depends how they failed.
Make -k uninstall if it's something you have no other bits for. Really, this is where making packages helps you no end, but you didn't do that, did you?
I have emacs here(Never used it) but it's linked against every standard library in the gnu/linux system, so I'm not surprised it failed. It's even linked against something called 'libhogweed.so'. Were they extracting the urine:-)?
Git is a much smaller package. They don't install large amounts of libraries (Any, afaict) but there may be includes, docs, and the source tarball as well as tmp files.