build: install gcr-viewer-window.h header file
build: install gcr-viewer-window.h header file

https://bugzilla.gnome.org/show_bug.cgi?id=658147

Distrotech/gcr,stefwalter/gcr,stefwalter/gcr,stefwalter/gcr,Distrotech/gcr,Distrotech/gcr,Distrotech/gcr,stefwalter/gcr