build: Drop ad hoc gitignore generation rules
build: Drop ad hoc gitignore generation rules

Instead, include Makefile.am.gitignore.

jigpu/clutter,ebassi/clutter,ebassi/clutter,Distrotech/clutter,djdeath/clutter,ebassi/clutter,djdeath/clutter,GNOME/clutter,Distrotech/clutter,GNOME/clutter,GNOME/clutter,Distrotech/clutter,Distrotech/clutter,Distrotech/clutter,jigpu/clutter,djdeath/clutter,GNOME/clutter,Distrotech/clutter,djdeath/clutter,ebassi/clutter,jigpu/clutter,ebassi/clutter,jigpu/clutter,GNOME/clutter,jigpu/clutter,djdeath/clutter,djdeath/clutter,jigpu/clutter