* lib/dirchownmod.c: Don't include fcntl.h; no longer needed. (dirchownmod): New arg FD. All callers changed. Use FD rather than opening the directory ourself, as opening is now the caller's responsibility. * lib/dirchownmod.h: Likewise. * lib/mkancesdirs.c: Include <sys/types.h>, for portability to older hosts that require <sys/types.h> before <sys/stat.h>. Include fcntl.h, savewd.h, and unistd.h, not dirname.h and stat-macros.h. (test_dir): Remove. (mkancesdirs): Return length of prefix of FILE that has already been made, or -2 if there is a child doing the work. Redo algorithm so that it is O(N) rather than O(N**2). Optimize away ".", and treat ".." specially since it might stray back into already-created areas. Use a subprocess if necessary. New arg WD; all users changed. MAKE_DIR function should now return 1 if it creates a directory that is not readable. Return -2 if a child process is spun off. * lib/mkancesdirs.h: Include <stddef.h>, for ptrdiff_t. Adjust signature to match code. * lib/mkdir-p.c: Include dirname.h, for IS_ABSOLUTE_FILE_NAME. (make_dir_parents): Use a subprocess if necessary. New arg WD; all users changed. * lib/savewd.c, lib/savewd.h: New files. * m4/savewd.m4: New file. * modules/mkancesdirs (Depends-on): Add fcntl. * modules/savewd: New file. * MODULES.html.sh (File system functions): Add savewd.