bug#20765: Python .egg files must not be compressed

[Ludovic Courtès]

Commit e5358a6 disables egg compression by augmenting ‘setup.cfg’ for
python-pillow only.

After:

--8<---------------cut here---------------start------------->8---
$ guix gc --references 
/gnu/store/jx7dmdrsgndzic0jqqs9hsljgxgs95kw-python-pillow-2.8.1
/gnu/store/1hcg2k1lfz7z64p27cjm156jj8y6ia1s-python-3.4.3
/gnu/store/29s2a1hfc47qa292pf9kd0k8m9djd3hf-libwebp-0.4.3
/gnu/store/61c1h5zlxcjq55z13i1n7inm0d1nfv0w-libtiff-4.0.3
/gnu/store/cpx9iibpdwi3wb81glpnnlxr9zra2iiv-bash-4.3.39
/gnu/store/fsy5s8wn2l542q05jn54lzp9wx5l9fdj-freetype-2.6
/gnu/store/j4w3bddy32p14mrd1a9d80435y50s3yz-zlib-1.2.7
/gnu/store/jawh8qxz9s9pn7mafq1gw9khpmq14qvl-python-setuptools-12.1
/gnu/store/jx7dmdrsgndzic0jqqs9hsljgxgs95kw-python-pillow-2.8.1
/gnu/store/jyk2nxd922wmls7xarx0npy11cvi2848-lcms-2.6
/gnu/store/lcsm84qj11fbg3wqwnpsl3x0p3b22f8s-python-wrapper-3.4.3
/gnu/store/mq8kb3z2qga5jb8vc3s832yp9pr4knm6-openjpeg-2.1.0
/gnu/store/n3xi1hzh43hz2i1qq78ajr1mrapif2pa-libjpeg-9a
/gnu/store/v7bvaklf40mmm9pq9bc3hilwvyj7dlwk-python-nose-1.3.4
/gnu/store/w29667jfv02s1hgmv0yp7nqyywvdv1fz-glibc-2.21
/gnu/store/z8xw06ns2xjc9v5iza2n7gprjhi7dda0-gcc-4.9.3-lib
--8<---------------cut here---------------end--------------->8---

Before:

--8<---------------cut here---------------start------------->8---
$ guix gc --references $(guix build python-pillow)
/gnu/store/1hcg2k1lfz7z64p27cjm156jj8y6ia1s-python-3.4.3
/gnu/store/cpx9iibpdwi3wb81glpnnlxr9zra2iiv-bash-4.3.39
/gnu/store/imi7gz1779h6559d5kh8w94p7kqx5fqv-python-pillow-2.8.1
/gnu/store/jawh8qxz9s9pn7mafq1gw9khpmq14qvl-python-setuptools-12.1
/gnu/store/lcsm84qj11fbg3wqwnpsl3x0p3b22f8s-python-wrapper-3.4.3
/gnu/store/v7bvaklf40mmm9pq9bc3hilwvyj7dlwk-python-nose-1.3.4
--8<---------------cut here---------------end--------------->8---

So clearly, I’d expect python-pillow to be more reliable now.

Now the question is how many packages end up installing compressed eggs,
and whether we can generalize that solution.

I think we should try doing the ‘setup.cfg’ dance in
python-build-system.scm after 0.8.3.

Thoughts?

Ludo’.