New fts module. * MODULES.html.sh (File system functions): Add fts, fts-lgpl. * lib/fts.c: Don't include "cycle-check.h" or "hash.h". (setup_dir, free_dir): New functions. (enter_dir, leave_dir): Define trivial alternatives of _LGPL_PACKAGE. Move to fts-cycle.c if !_LGPL_PACKAGE. (HT_INITIAL_SIZE, ENTER_DIR): Remove. All uses removed. (LEAVE_DIR): Fix typo: pass Fts and Ent to leave_dir. (struct Active_dir, AD_compare, AD_hash, enter_dir, leave_dir): Move to fts-cycle.c. (fts_open): Use setup_dir. (fts_close): Use free_dir. (fts_read): Have just one copy of the ENTER_DIR code rather than three. This adds a label and some gotos, but the alternatives were messier. Check for memory allocation failure when entering a dir. (fts_stat) [_LGPL_PACKAGE]: Bring back glibc cycle detection code. * lib/fts_.h (_LGPL_PACKAGE) [defined _LIBC]: New macro. (FTS): New member fts_cycle, that is a union that contains the old active_dir_ht and cycle_state. All uses changed to mention fts_cycle.ht and fts_cycle.state. * lib/fts-cycle.c: New file, containing GPL'ed code migrated out of fts.c, with the following changes: (setup_dir, free_dir): New functions. (enter_dir): Now returns bool. Return true if successful, false if memory exhausted. All callers changed. Do not bother partly cleaning up on memory allocation failure; that is free_dir's job. However, free ad if hash_insert fails, to avoid memory leak. (enter_dir, leave_dir): Accommodate change to FTS by inspecting fts->fts_options to see which union member to use. * m4/fts.m4 (gl_FUNC_FTS_CORE): Renamed from gl_FUNC_FTS. (gl_FUNC_FTS, gl_FUNC_FTS_LGPL): New macros. * lib/unlinkdir.h (cannot_unlink_dir) [UNLINK_CANNOT_UNLINK_DIR]: Now a macro, to pacify GCC.

--- a/MODULES.html.sh
+++ b/MODULES.html.sh
@@ -1815,6 +1815,8 @@
   func_module file-type
   func_module fileblocks
   func_module filemode
+  func_module fts
+  func_module fts-lgpl
   func_module isdir
   func_module lchown
   func_module makepath