codegen: Do not create a shadowing *_private_offset variable in GtkModule
codegen: Do not create a shadowing *_private_offset variable in GtkModule

This is globally available since df56f916e52e5efe3876afed59a6190f6cead1c8

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