heap. Change fatal error to avoid confusion with cygheap.
* spawn.cc (linebuf::finish): New function.
(linebuf::add): Cosmetic change.
(spawn_guts): Only avoid building windows command line if the program being
executed was actually mounted with -X. Don't return E2BIG if we hit the 32K
size and we're executing a detected cygwin program. Just silently truncate the
windows command line, instead.