* fhandler_process.cc (struct dos_drive_mappings): Use malloc/free

	* fhandler_process.cc (struct dos_drive_mappings): Use malloc/free
	rather than cmalloc/cfree.  Check return value from malloc before
	using it.
	(struct heap_info): Ditto.
	(struct thread_info): Ditto.  Rename from stack_info.  Rename members
	and local variables accordingly.
	(thread_info::thread_info): Store stack and TEB addresses.
	(thread_info::fill_if_match): Print "teb" if a TEB address has been
	found.  Special case for WOW64, explain why.
	(format_process_maps): Fetch PEB address.  Print MEM_RESERVE regions
	with equal signs to distinguish them from PAGE_NOACCESS regions.  Fix
	printing of 'p' and 's' to differ between MEM_PRIVATE and MEM_MAPPED
	pages, as on Linux.  Print 'g' instead of 'p for PAGE_GUARD pages.
	Print PEB and SharedUserData area if recognized.