python.pkgs.pkgconfig raises an exception on missing packages since
version 1.5.0. Previously those errors were just silently ignored. That
worked fine, since the packages are only missing at runtime (when they
are not really needed) but present at buildtime.
Since this fails the tests now, we just add the packages to
PKG_CONFIG_PATH at runtime. This does not add additional runtime
dependencies. Still, it would be nicer if the sage testssuite would not
test the buildsystem at runtime in the first place.
The breakage was originally caused by the pkgconfig update in
1efa71616f.
This reverts commit 4900bbee17.
The issue that was supposed to fix is now fixed by lazy-loading rpy2 and
makign sure scipy is loaded before that.
That is not quite as nice, but preloading is now causing its own issues
with openblas 0.3.4:
https://github.com/xianyi/OpenBLAS/issues/1936
Those were removed because they were added to openblas itself. There was
an error with that however and it will take some time until the fix
makes its way through staging. For the time being, reverting this part
of 26d5d030fe will fix the sage build.
This commit should be reverted once
408eacbc89 is in master.
