Merge branch '4524_cleanup'

Merge branch '4524_cleanup'

* 4524_cleanup: (41 commits)
  Update po/*.po files.
  Remove src/editor/.gitignore.
  Indentation using GNU indent-2.2.13.
  clang: fix `-Wconstant-conversion` warning
  clang: fix `-Wpointer-sign` warning
  buildsys: prefer gnu indent (gindent) to bsd indent if available
  buildsys: update ax_gcc_func_attribute to fix fallthrough detection
  clang: fix `-Wimplicit-fallthrough` warning
  clang: fix `-Wconditional-uninitialized` warnings
  buildsys: fix build on macOS with libssh2 present via homebrew
  m4: add Werror when checking for compiler flags
  (path_trunc): optimization.
  (vfs_path_build_url_params_str): minor refactoring.
  (vfs_path_from_str_uri_parser): fix coding style.
  (mc_search__glob_translate_to_regex): reduce variable scope, refactor.
  src/filemanager/find.c: remove unneeded intialization of local variables.
  (do_find): minor refactoring.
  src/filemanager/find.c: ret rid of string duplication.
  (search_content): reduce variable scope.
  (do_find): fix coding style.
  ...