Merge branch '2888_cleanup'

Merge branch '2888_cleanup'

* 2888_cleanup: (34 commits)
  (exec_get_export_variables_ext): use g_new0() for stable test results.
  Implement quick and easy disable of xdg-open usage.
  Sync with gnulib 40f82767840187c20051ca99385f75a42f92de99.
  Add extra checks in macro engine.
  Ticket #2935: update uc1541 extfs plug-in up to version 2.5.
  (del_widget): fix memory leak.
  (editcmd_dialog_replace_prompt_show): fix string truncations.
  Portability: rename some str_class members
  Portability: ESC_CHAR is defined in /usr/include/langinfo.h in some systems
  Cleanup code related to GLib < 2.12.
  Portability: use g_ascii_strtoll instead of strtoll, atoll and atof.
  Fix crash when user menu is called in editor with no filename.
  Keep some edit window parameters during file reloading.
  Fix editor crash in "Save as..." command.
  Ticket #2841: adjust i18n label sizes in learn key dialog.
  Disable the localized output of utilities such as - ls, git, etc..
  (add_widget_autopos): don't access to NULL widget.
  Parenthesis around some -1.
  src/filemanager/mountlist.c: use GLib functions to allocate/free memory.
  Sync with gnulib 613bcb6205cf2b64d835c19074c5a7e7c6cb99eb
  ...