allow wxPython to be installed as an extension

[mboisson]

Also using the 'build wheel + pip install wheel' mechanism, as otherwise, it would ignore the install prefix

[akesandgren]

LGTM

[akesandgren]

Going in, thanks @mboisson!

[boegel]

Test report by @boegel

Overview of tested easyconfigs (in order)

• SUCCESS wxPython-4.0.4-GCC-8.2.0-2.31.1-Python-3.7.2.eb
• SUCCESS wxPython-4.0.4-GCC-8.2.0-2.31.1-Python-2.7.15.eb

Build succeeded for 2 out of 2 (2 easyconfigs in total)
node2643.swalot.os - Linux centos linux 7.8.2003, x86_64, Intel(R) Xeon(R) CPU E5-2660 v3 @ 2.60GHz (haswell), Python 3.6.8
See https://gist.github.com/2bf6852896734bd274969da3e7a17230 for a full test report.

[boegel]

The changes made here seem to be breaking the installation of wxPython-4.0.7.post2-GCC-8.3.0-Python-3.7.4.eb (which installs fine with EasyBuild v4.3.1). The sanity check fails because .so symlinks are missing in the installation:

== sanity checking...
...
  >> file 'lib/python3.7/site-packages/wx/libwx_baseu-3.0.so' found: FAILED
  >> file 'lib/python3.7/site-packages/wx/libwx_gtk3u_core-3.0.so' found: FAILED

Can someone confirm this?

[mboisson]

Mmm, these symlinks are indeed not in the lib/pythonX.Y/site-packages/wx/ folders, they are in the lib folder. I guess the sanity_checks have to be changed depending on the installation method ?

[boegel]

Not that it's only a problem for wxPython-4.0.7, the wxPython-4.0.4 easyconfigs still work fine?!

Do you mind opening a PR to fix this before we fork off things for the EasyBuild v4.3.2 (which we'll do tomorrow or Wed)?

[mboisson]

Mmm, well I'm not in a situation to be able to test those EasyConfigs directly (I don't have this GCC, nor those versions of python)... The EasyConfig in which I used this is one for wxWidgets in which wxPython is installed as multi_deps extension.

I thought it might be just because the installation methods are not the same, and therefore result in different symlinks, but that it does not work for 4.0.7, but does for 4.0.4, that is mind-boggling.

[boegel]

Let's follow up in easybuilders/easybuild-easyconfigs#11790, it's too difficult to follow up on problems in merged PRs...