Change _function() to function() throughout.

Change _function() to function() throughout.
* cygwin.din: Remove last vestiges (?) of newlib wrappers.
* cygthread.cc (cygthread::detach): Always wait for event or suffer an
apparently inavoidable race.
* dcrt0.cc (dll_crt0_1): Allocate threads after stack has been relocated.
* debub.cc (lock_debug): Don't acquire lock on exit.
* fork.cc (fork_child): Recreate mmaps before doing anything else since Windows
has a habit of using blocks of memory in the child that could previously have
been occupied by shared memory in the parent.
* mmap.cc (fhandler_disk_file::fixup_mmap_after_fork): Issue error here and
provide some details about what went wrong.
(fixup_mmaps_after_fork): Remove error message.
* shared.cc (open_shared): Move warning message so that more detail is
possible.
* sigproc.cc (sigproc_init): Initialize sync_proc_subproc to avoid a race.
(sigproc_terminate): Specifically wait for process thread to terminate.