codegen: Include header for base-symbols when connecting vfuncs
codegen: Include header for base-symbols when connecting vfuncs

This eases the handling of types which are split over different headers.

GNOME/vala,GNOME/vala,frida/vala,GNOME/vala,GNOME/vala,frida/vala,frida/vala,frida/vala,frida/vala