Pulling in python from a buildlink3.mk file

[Martijn van Buul <pino%dohd.org@localhost>]

Hello,

I've been trying to package the sigrok software suite (see 
http://www.sigrok.org/ ). I haven't created a package for almost a decade,
so please bear with me...

Sigrok is a software suite for logic analyzers, DSO's and similar devices. 
It is split in half a dozen separate projects, and I'm running into
problems with one of them - libsigrokdecode. This library facilitates 
decoding of various protocols (UART, SPI, I2C etc) and the actual decoders
are implemented in python3, and the library is therefore linked against 
python, using

PYTHON_VERSIONS_INCOMPATIBLE = 27 # requires at least python 3.2
.include "../../lang/python/application.mk"

My problem is that I'm not sure how to correctly register this dependency
in a buildlink3.mk file. I can Make It Work by doing something like

PYTHON_VERSIONS_INCOMPATIBLE += 27 # requires at least python 3.2
.include "../../lang/python/pyversion.mk"

but that just seems fragile and wrong. How do I ensure that the correct version
of python is being pulled in? I've gleaned through the other packages, and
there's only one package doing the same (devel/libpeas)

fwiw, I have posted the embryonic package to

http://pastebin.com/81qxFT2q  (Makefile)
and
http://pastebin.com/wW8ninFe  (buildlink3.mk)

Thank you,

Martijn
-- 
Martijn van Buul - pino%dohd.org@localhost