* sec_helper.cc (cygpsid::get_id): Move Samba SID->uid/gid mapping
	from get_sids_info here.
	(get_sids_info): Vice versa.
	* security.cc (convert_samba_sd): New static function to map a Samba
	security descriptor to a security descriptor with UNIX users and groups
	converted to Windows SIDs per RFC 2307 mapping.
	(check_file_access): Call convert_samba_sd on Samba security
	descriptors.
	* exception.h (exception::exception): Install vectored exception
	handler rather than vectored continue handler.
	* libc/include/machine/_default_types.h: Define unsigned type using
	signed type macros in case unsigned type macros are not available.
Merge branch 'Cygwin' into develop