Fix coalescing operator semantics check.

The left operand was not put in any code block
before the check, thus it wasn't able to transform itself.

Fixes bug 691514.
codegen: Support "foo is G"
gdk-x11-3.0: Switch to GIR
gtk+-3.0: Update to 3.11.3+
glib-2.0: Add abs() to short type

Fixes bug 722067
glib-2.0: Fix short.abs() to be an instance method
glib-2.0: Add G_LOG_2_BASE_10 constant

Fixes bug 722466
gtk+-3.0: Nullable GtkListBox::row_selected.row

https://bugzilla.gnome.org/show_bug.cgi?id=722490