(do_background): Set current_dlg to NULL for the child process.
* dialog.h (do_complete_refresh): Don't use we_are_background.
* file.h: Remove dependency on background.h.
* background.h: Define we_are_background. Move mc_message() ...
* wtools.h: ... here.
* key.h: Don't define we_are_background.
* slint.c (mc_refresh): Use current_dialog instead of
we_are_background to fix compilation without WITH_BACKGROUND.
defined.
* fsusage.c: Rearrange the includes. Define HAVE_QNX_MOUNT
for old QNX and use it instead of __QNX__.
* mountlist.c: Likewise.
* keyxdef.c: Define HAVE_QNX_KEYS for old QNX and use it instead
of __QNX__.
used by message () as printf pattern, so "%s" has to be added
if plain string must be shown but printf conversion
specification(s) may be there.
* view.c (do_view_init): ditto
* user.c (debug_out): ditto
* utilunux.c (close_error_pipe, check_error_pipe): ditto
* background.[ch], vfs/util-alone.c (message_1s): third parameter
constified
