not already defined. Use __SIGRTMIN if available.
(target_signal_from_host): Remove SIGRTMIN block.
(do_target_signal_to_host): Remove SIGRTMIN block; check that
the signal is within the realtime range.
* signals/signals.c (signals): Remove conditional compilation around
Mach-specific signals. Move them to after TARGET_SIGNAL_DEFAULT.
(target_signal_from_name): Loop until TARGET_SIGNAL_LAST.
* signals/signals.c: Include "server.h" in gdbserver build.
(target_signal_from_name): Don't use STREQ.
(_initialize_signals): Likewise. Don't include function in
gdbserver build.