* cygheap.cc (cygheap_setup_for_child): Add api_fatal to catch failing

* cygheap.cc (cygheap_setup_for_child): Add api_fatal to catch failing
MapViewOfFileEx.
* cygthread.cc (cygthread::stub): Previous change to make diagnostic output
more informative was really a bust.  Try again.  Capture previous name in a new
field in cygthread for diagnostic purposes.
(cygthread::cygthread): Ditto.
(cygthread::release): Add an argument to control whether h should be cleared or
not.
(cygthread::terminate_thread): Use 'inuse' for tests rather than 'h'.
(cygthread): Add some diagnostic fields.
(cygthread::release): Add an argument.
* pinfo.cc (proc_waiter): Accommodate change to cygthread::release.