* cygheap.h (struct init_cygheap): Remove shared_h and mt_h members.

	* cygheap.h (struct init_cygheap): Remove shared_h and mt_h members.
	* fhandler_tape.cc (mt): Define as DLL shared area in
	.cygwin_dll_common instead of as dynamically allocated area.
	Change referencing throughout.
	* mtinfo.h (mt_h): Remove entirely.
	(mt): Remove extern declaration.
	* shared.cc (cygwin_shared_area): New global cygwin_shared
	variable located in .cygwin_dll_common.
	(offsets): Define shared region addresses descending from
	cygwin_shared_address.
	(open_shared): Replace usage of SH_CYGWIN_SHARED by SH_USER_SHARED.
	(memory_init): Set cygwin_shared just by pointing to cygwin_shared_area.
	* shared_info.h (shared_locations): Remove SH_CYGWIN_SHARED and
	SH_MTINFO.
	(cygwin_shared_address): Define as DLL start address.
	* tty.h (tty_min::tty_min): Remove constructor.