This is the last piece of the puzzle to get all tests passing with
MediaGoblin and its Python dependencies, I believe.

Unfortunately, I can't get the package quite right.  Here's where it
fails:

Making install in overrides
make[2]: Entering directory '/tmp/guix-build-gst-python-1.6.1.drv-0/gst-python-1.6.1/gi/overrides'
make[3]: Entering directory '/tmp/guix-build-gst-python-1.6.1.drv-0/gst-python-1.6.1/gi/overrides'
 /gnu/store/nl4g5nzfdy6fad6i1zgxp1gin5c73b47-coreutils-8.24/bin/mkdir -p '/gnu/store/612jc932fk766brficmv11ddvgck6qgc-python-pygobject-3.18.0/lib/python3.4/site-packages/gi/overrides'
 /gnu/store/x8dmdlrn5qn0wrbcnngj55y3ab73h0pp-bash-4.3.42/bin/bash ../../libtool   --mode=install /gnu/store/nl4g5nzfdy6fad6i1zgxp1gin5c73b47-coreutils-8.24/bin/install -c   _gi_gst.la '/gnu/store/612jc932fk766brficmv11ddvgck6qgc-python-pygobject-3.18.0/lib/python3.4/site-packages/gi/overrides'
libtool: install: /gnu/store/nl4g5nzfdy6fad6i1zgxp1gin5c73b47-coreutils-8.24/bin/install -c .libs/_gi_gst.cpython-34m.so /gnu/store/612jc932fk766brficmv11ddvgck6qgc-python-pygobject-3.18.0/lib/python3.4/site-packages/gi/overrides/_gi_gst.cpython-34m.so
/gnu/store/nl4g5nzfdy6fad6i1zgxp1gin5c73b47-coreutils-8.24/bin/install: cannot create regular file '/gnu/store/612jc932fk766brficmv11ddvgck6qgc-python-pygobject-3.18.0/lib/python3.4/site-packages/gi/overrides/_gi_gst.cpython-34m.so': Permission denied
Makefile:428: recipe for target 'install-pygioverridesexecLTLIBRARIES' failed

So, no surprise that this fails... it's trying to install to another
package in the store.

There must be another way we do this for other gobject introspect using
packages?  Could someone help me out please?  I'd appreciate it!

 - Chris