build-3rdparty.py: remove default value for `variant` variable

[adrianopol]

This script is used for building 3rd-party dependencies when a user passes --build-3rdparty=dep1,dep2,... option to the scons utility like:

scons -Q --build-3rdparty=openfec --enable-tests test

variant argument is mandatory when running the script (see line variant = sys.argv[4] and below), but the function makeflags() has empty default empty-string value for it (which is used for example for libuv dependency):

def makeflags(workdir, toolchain, env, deplist, cflags='', ldflags='', variant='', pthread=False):

This is a bug.

Acceptance criteria

• variant should never be assumed something different from debug or release in build-3rdparty.py script
• some CI builds may be affected by this change; they should also be fixed

Implementation details

• fix makeflags() signature (remove default value for variant argument)
• look for all places where it is called and pass global variant variable explicitly

[gavv]

Because of this issue --enable-debug-3rdparty does not work for all dependencies

[gavv]

Seem that current code does not have this problem.

[gavv]

https://github.com/roc-streaming/roc-toolkit/blob/229a74eb3ba2229017203de63fe8798813e87185/scripts/scons_helpers/build-3rdparty.py