geda-gaf: clean up install
geda-gaf devel 1.9.1
Don't use a tarball for HEAD
bitchx: specify plugins to build

bitchx has no "--disable-plugin" option, so this is the next best way
to disable plugins that won't build (e.g. europa).

Fixes #31282.
Closes #31284.

Signed-off-by: Misty De Meo <mistydemeo@gmail.com>