Add some "3.9" attributes to srcs in gnuradio packages And update
packages using GR3.8 and that are incompatible yet with GR3.9 to use
GR3.8 explicitly.
Now that volk is packaged, we can use our build and save some closure
space for those that have more then 1 version of gnuradio installed.
Also, simplify a bit how attributes are inherited in the expression.
- Write a `mkDerivation` and `mkDerivationWith` function for gnuradio,
like qt5.
- qradiolink, gqrx: Use gnuradio's callPackage and mkDerivation.
- Use gnuradio.callPackage to define all gnuradio.pkgs.
- Move all gnuradio packages expressions to pkgs/development/gnuradio-modules/ -
modeled after Python's.
- Add more paths to gnuradio's wrapper - add the extra packages as
python modules, and add their executables with proper env vars
wrapping.
Co-authored-by: Frederik Rietdijk <fridh@fridh.nl>