gplugin/gplugin

Hide properties type on FreeBSD.
develop
2020-02-29, Elliott Sales de Andrade
412d67a92be9
Hide properties type on FreeBSD.

In `perl.h`, there is:
```
#ifdef I_LIBUTIL
#include
#endif
```
and on FreeBSD, `I_LIBUTIL` is defined in Perl's `config.h`. That header does
not really appear to be necessary for Perl, but it has the side effect of
declaring a `properties` type. This is a generic name used in our code base, so
we hack around it with the preprocessor. Preferably, FreeBSD would fix that in
their Perl port in the future.
gplugin-gtk-viewer/data/window.ui
gplugin-gtk-viewer/gplugin-gtk-viewer-window.c
gplugin-gtk-viewer/gplugin-gtk-viewer.c
gplugin-gtk/data/plugin-info.ui
gplugin-gtk/gplugin-gtk-plugin-info.c
gplugin-gtk/gplugin-gtk-store.c
gplugin-gtk/gplugin-gtk-view.c
gplugin/gplugin-core.c
gplugin/gplugin-file-tree.c
gplugin/gplugin-loader.c
gplugin/gplugin-manager.c
gplugin/gplugin-native-loader.c
gplugin/gplugin-native-plugin.c
gplugin/gplugin-options.c
gplugin/gplugin-plugin-info.c
gplugin/gplugin-plugin.c
gplugin/gplugin-private.c
gplugin/gplugin-query.c
gplugin/gplugin-version.c
lua/gplugin-lua-core.c
lua/gplugin-lua-loader.c
lua/gplugin-lua-plugin.c
lua/gplugin-lua-test-lgi.c
perl/gplugin-perl-core.c
perl/gplugin-perl-loader.c
perl/gplugin-perl-plugin.c
python/gplugin-python3-core.c
python/gplugin-python3-loader.c
python/gplugin-python3-plugin.c
python/gplugin-python3-test-pygobject.c
python/gplugin-python3-utils.c
tcc/gplugin-tcc-core.c
tcc/gplugin-tcc-loader.c
tcc/gplugin-tcc-plugin.c