search for: _executeshcmd

Hi, A feature I've wanted in lit for a while is a having a timeout per test. Attached are patches that implement this idea. I'm e-mailing llvm-dev rather than llvm-commits because I want to gather more feedback on my initial implementation and hopefully some answers to some unresolved issues with my implementation. Currently in lit you can set a global timeout for all of the tests but

I see many tests that are prefixed with "requires: shell". A quick search over the codebase shows 101 tests that contain this directive. This basically means there are 101 tests that say "I don't support running on Windows". I would like to get this number to 0. Ironically, many of these tests can be made to run on Windows simply by removing the requires: shell line.