This patch almost completes the build side of the libgcc moves. It
moves the libgcc_tm_file support to libgcc/config.host (tm_file), where
it belongs. It builds on a patch Paolo posted some time ago, with some
minor corrections (introducing the required dependencies on the
generated libgcc_tm.h). I've removed libgcc_tm.h from tm.h and include
the file directly in all libgcc sources that currently include tm.h.
Everything else is pretty mechanical, I believe.
Tested as described in the previous submissions.
Rainer