fails to build with python3.8

[mwhudson]

Hi, sorry if this isn’t the appropriate place for this report. kopanocore fails to build when python3.8 is the default, which will be the case soon in the development version of Ubuntu. You can see the failure here https://launchpad.net/ubuntu/+source/kopanocore/8.7.0-5ubuntu7/+build/18608464 but the log isn’t terribly interesting. The cause of the failure is the change in Python 3.8 to no longer link Python extensions to libpython; this means that pkg-config --libs python3 is empty and this makes ./configure believe Python is not available. As AFAICT checking for the non-emptiness of $PYTHON_LIBS is just a sanity check, it could probably be dropped entirely.

[longsleep]

@mwhudson Kopano is embedding Python for (optional) Python plugin support. Since the embedding in Python 3.8 has changed, the normal pkg-config --libs python3 does not yield anything and rightfully errors. To support building with Python 3.8, configure needs to use pkg-config --libs python-3.8-embed. A patch for this should be possible on distribution level.

[longsleep]

The fix to support build with Python 3.8 has been merged. See https://github.com/Kopano-dev/kopano-core/commit/00669f113dfb77909878cae06f0f6082c973f1b0 for details.