* child_info.h (CURR_CHILD_INFO_MAGIC): Reset.

* child_info.h (CURR_CHILD_INFO_MAGIC): Reset.
(child_info_fork::heaptop): Remove obsolete element.
(child_info_fork::heabbase): Ditto.
(child_info_fork::heapptr): Ditto.
(child_info_fork::mount_table): New element.
(child_info_fork::myself_addr): Ditto.
* dcrt0.cc (dll_crt0_1): Set mount_table and myself_addr when forking.
(initial_env): Add newline to "sleeping" message.
* dll_init.cc (reserve_upto): Accommodate cygwin heap when freeing memory.
Make debugging output a little more descriptive.
* fork.cc (fork_parent): Save mount_table and myself_addr.
* pinfo.cc (myself_addr): New variable.
(set_myself): Pass PID_MYSELF flag to init.
(pinfo::Init): Honor PID_MYSELF.  Save address where myself shared memory
resides in myself_addr, for fork.
* pinfo.h (myself_addr): Declare.
* shared.cc (memory_init): On fork, use previously saved address for location
of mount table.
* include/sys/cygwin.h (PID_MYSELF): New value.
* dtable.cc (dtable::stdio_init): Don't pass access type to
init_std_file_from_handle.  It's always the same.
(dtable::init_std_file_from_handle): Remove access type argument.  Assume
read/write.
* dtable.h (dtable::init_std_file_from_handle): Ditto for declaration.
* exceptions.cc (try_to_debug): Don't try to debug if already being debugged.
* fhandler_console.cc (shared_console_info_save): New variable.
(fhandler_console::get_tty_stuff): Save address of shared console stuff for
fork.