Merge branch '2888_cleanup'
* 2888_cleanup:
Fix of DOXYGEN docs: @return instead of @returns
src/filemanager/command.c: add DOXYGEN doc little little code cleanup.
(enter): use GString instead of hand-made memory (re)allocation.
Clarify of sig_atomic_t usage (got from Mutt).
Define winch_flag as volatile sig_atomic_t.
Fixups of SIGWINCH handling.
Don't exit after migration of configuration files.
Tweak sources for --with-x/--without-x option.
Init file highlighting only in full mode.
(exit_subshell): return gboolean instead of int.
lib/strutil/strverscmp.c: add missing include of config.h.
(fish_linear_abort): type accuracy.
(fish_file_store): remove unnecessary 'was_error' variable.
(fish_file_store): type accuracy to avoid counter overflow while copiyng huge files.
(ftpfs_file_store): type accuracy and simplify conditions.
Ticket #2888: code cleanup before 4.8.7 release.