Merge branch '3915_cleanup'

Merge branch '3915_cleanup'

* 3915_cleanup: (24 commits)
  Update po/*.po files.
  src/filemanager/panelize.c: fix coding style.
  Sync with gnulib 844f63f9576ebb74fde62e5017bf838c69db22c4.
  Sync with gnulib 1ff0e9684bb83a8277ffe22ac125ce7e90f6702b.
  Sync with gnulib e96dcbcbc5142bd04c6c2e9e4595d9bea910fb3b.
  Sync with gnulib 23671eec22f5221a2dff50942f24c41bcf9caeaf.
  Sync with gnulib 8ae091f7c8cd35cc7dff82c544d04da6fd095e11.
  Sync with gnulib 4d4877e6c2123c4862c321f3eab28a55bf886216.
  Sync with gnulib cbc85bb67fc628349e0351b835efc9e91cd0482f.
  Sync with gnulib be9e66b37c948df517ee905b4a9689a50946409c.
  (make_symlink): rename variable.
  (do_move_dir_dir): rename variables.
  (copy_dir_dir): rename variables.
  misc/syntax/Syntax.in: simplify regex for PO and CUDA syntaxes.
  misc/syntax/Syntax.in: fix regex for Meson syntax.
  dir_list: fix memory leak when list is free'd.
  Sync with gnulib f7a6286e04209da1bc7b1820002b6a5c32638369.
  Sync with gnulib d1327df1f1c9bae26571e6699800c8d1c4712afb.
  Sync with gnulib fa3e2ad20d10d648cc74a5d320ce531a80ff7b1f.
  Sync with gnulib 74c29c68bba3fe7c2f02eb3fc9f7ef196cec1bc6.
  ...