Fixes #7

Because it currently causes so many warnings about #warning (in the
gtksourceview headers) being a GNU-only extension.

This file needs to exist because ro was added to LINGUAS.

This doesn't contain any actual Romanian translations yet.

So that Glom can work with recent versions of PostgreSQL.
See libgda issue: libgda#24

Strangely, popup() is not deprecated in GTK+ 4.

Because that is the current version, and that makes it easier to
build against the not-deprecated API.

And test this.
This regression was probably introduced by the conversion to use
auto with C++11.

This was probably a regression since converting to use of auto with
C++11.

This bad test was revealed by the correction to return EXIT_SUCCESS,
instead of false, from main().

Noticed by a g++ warning.

Add Romanian Translations for film_manager, lesson_planner, music_collection and smallbusiness examples.

So that when this fails, we get a more obvious clue that this is
what failed.

This seems to fail currently due to this libgda bug:
ttps://gitlab.gnome.org/GNOME/libgda/issues/24

Recent versions of gcc helpfully notice that this was passing an
enum value for a bool parameter:

warning: enum constant in boolean context [-Wint-in-bool-context]

Minor const correction.
This was broken by a cherry-picked commit from the gtkmm-4v4 branch.