* process.cc (process::process): Only notice that signal_arrived is
	NULL in debug output.
	* cygserver_ipc.h (ipc_set_proc_info): Add bool parameter to specify
	whether or not to send signal_arrived.
	* shm.cc (client_request_shm::client_request_shm): Call
	ipc_set_proc_info with bool parameter set to true to not send
	signal_arrived.
release/1.7.29
	* cygwin.sc.in: (Temporarily?) workaround serious ld bug which
	truncates symbols in certain computations to 32 bit.  See
	https://sourceware.org/bugzilla/show_bug.cgi?id=16821