set.
* exceptions.cc (sig_handle_tty_stop): Don't reset sigCONT event since it is
reset automatically.
* fork.cc (fork): Remove obsolete usage of PID_SPLIT_HEAP.
* include/sys/cygwin.h: Ditto.
* sigproc.cc (sig_send): Use sigframe init method to set frame since it checks
for previous ownership of the frame.
* sigproc.h (sigframe::init): Accept an "is_exception" argument.