This series merges in gdb's changes to default_target_compile, updating them to follow newer conventions at the same time.
I tested this using various parts of the gdb test suite (in particular Go and Rust). I also verified that, with this series in place, gdb does not use its monkey-patched code from future.exp. I didn't attempt to further parameterize default_target_compile, though I think that would be a good thing to do. Tom
