On Fri, 2018-03-23 at 01:22 +0100, Maren Hachmann wrote:

- Btw. as far as I understand, our Windows versions come with pip as
part of the python installation, to facilitate installing extension
dependencies (Eduard will know more about this). Doesn't look like a
virtualenv to me, though.

Pip may be all that's required, you don't need virtualenv to have a
custom prefix:

https://stackoverflow.com/questions/2915471/install-a-python-package-in
to-a-different-directory-using-pip

I believe this eliminates one of the problems, no extra deps (on
windows at least) and removing binaries from the conf.

Martin,

• pip is currently *not* included in Windows builds (it was for a short time when I last updated the devlibs - which we do not use anymore - but it was completely experimental back then and usage was not straightforward with some things not working as one would expect). Investigating the usage of pip is on my todo list but I did not find the time so far.
  
• Even *if* we get pip do work properly you need to be aware that it's generally not possible to install any modules with it that contain binary components. pip is not magically allowing us to compile stuff on-the-fly. It can only work for pure Python modules (and even that fails occasionally, especially if any non-standard setups are attempted - like the one you seem to suggest).