* winsup.h (child_copy): Change prototype to match new functionality.

* winsup.h (child_copy): Change prototype to match new functionality.
* cygheap.cc (cygheap_fixup_in_child): Accommodate new child_copy arguments.
* dcrt0.cc (dll_data_start): Move definition here from fork.
(dll_data_end): Ditto.
(dll_bss_start): Ditto.
(dll_bss_end): Ditto.
(handle_fork): New function.  Called when forked to deal with fork issues and
copy data to this process from the parent.
(dll_crt0_0): Call handle_fork when _PROC_FORK condition.
(dll_crt0): Don't copy user_data when we've forked.  Don't zero first element
of main_environment ever.
(cygwin_dll_init): Ditto.
* fork.cc (child_copy): Rename from fork_copy and change arguments so that each
pair of things to copy gets its own descriptor.
(frok::child): Remove fixup_mmaps_after_fork call here.  Move to handle_fork in
dcrt0.cc.
(frok::parent): Use child_copy rather than fork_copy and accommodate changes in
parameters.
* exceptions.cc (setup_handler): Delay test of whether we're locked until after
GetThreadContext has been called since there are apparently cases where
SuspendThread does not cause an immediate thread suspension.