Prevent SIGPIPEs in deactivate_process(). * process.c (deactivate_process): Use Lstream_close_noflush on output pipe instead of Lstream_close. * lstream.c (Lstream_close_noflush): New. Factored out of Lstream_close. (Lstream_close): Use Lstream_close_noflush. * lstream.h (Lstream_close_noflush): Declare it.