(GetCachedVolumeInformation): Use xmalloc, xfree and xstrdup.

(GetCachedVolumeInformation): Use xmalloc, xfree and xstrdup.
(add_volume_info): Use xstrdup.
(init_environment): Call _access.
(check_windows_init_file): Call _close.
(init_user_info): Call _putenv.
(init_environment): Call _putenv and _strdup.
(init_ntproc): Reset volume info cache on startup.
(unc_volume_file_attributes):
(open_unc_volume): Make arg const.
(gettimeofday): Use struct timeb, not struct _timeb.
(map_w32_filename, read_unc_volume): Fix compile warning.
(sys_strerror): Use sys_nerr instead of _sys_nerr.  Use
sys_errlist instead of _sys_errlist.
(get_emacs_configuration_options): New function.