throughout for subkey name buffer size.
* fhandler_socket.cc (search_wsa_event_slot): Use MAX_PATH instead of
CYG_MAX_PATH for mutext name buffer size.
(fhandler_socket::init_events): Ditto.
* fhandler_virtual.cc (fhandler_virtual::opendir): Check path length
against PATH_MAX instead of against CYG_MAX_PATH.
* registry.cc (get_registry_hive_path): Use PATH_MAX instead of
CYG_MAX_PATH for registry value path buffer size.
* shared.cc (open_shared): Use MAX_PATH instead of CYG_MAX_PATH
for shared memory name buffer size.
* thread.cc (semaphore::semaphore): Use MAX_PATH instead of CYG_MAX_PATH
for semaphore name buffer size.
* uinfo.cc (cygheap_user::env_userprofile): Use PATH_MAX instead of
CYG_MAX_PATH for temporary path name buffer size.
* winf.h (LINE_BUF_CHUNK): Define as MAX_PATH * 2.
* include/sys/dirent.h: Include sys/limits.h. Define name buffer sizes
using NAME_MAX.