* gdbserver/configure.srv: New file.
* gdbserver/configure.in: Use configure.srv instead
of the host/target makefile fragments. Set GDBSERVER_DEPFILES
from it.
* gdbserver/configure: Regenerated.
* gdbserver/terminal.h: New file.
* gdbserver/Makefile.in: Update for configure changes. Remove
more unneeded include paths.
