* dir.c: Use canonical code from autoconf manual for dirent include.
[_D_NAMLEN]: Redefine NAMLEN using this.
(dir_contents_file_exists_p): Use NAMLEN macro.
(read_dirstream) [_DIRENT_HAVE_D_NAMLEN]: Only set d_namlen #if this.
(D_NAMLEN): Macro removed.
(FAKE_DIR_ENTRY): New macro.
(dir_contents_file_exists_p): Test HAVE_D_NAMLEN instead of using D_NAMLEN.
(read_dirstream): Return a struct dirent * for new glob interface.
(init_dir): Function removed.
(dir_setup_glob): New function.
(dir_contents_file_exists_p) [__MSDOS__]: Call it on FILENAME and process
the result instead of FILENAME itself.
(file_impossible_p) [__MSDOS__]: Likewise.
Part of MSDOS/GO32 port from DJ Delorie <dj@ctron.com>.