@dc42 nice, I recompiled it on mac, was faster to get everything up and running without messing out working envinronments for other stuff on my main win desktop and compiling is fast enough that the speed of the mac is not that important 😄 .. brew is a nice addon to osx 🙂 .. brew installs (GNU Tools for Arm Embedded Processors 9-2019-q4-major) 9.2.1 20191025 (release) [ARM/arm-9-branch revision 277599] so exactly what you say you are using for 3.1.1 and the issue is only with src/GCodes/GCodeBuffer/ExpressionParser.cpp the conv.Accumulate is called with wrong number of parameters .. probbly ReprapFirmware:v3-dev vs RRFLibraries:dev at point I was doing a clone were out of sync (I see that whole section is new) ... I just needed to do the quick read of the ADC so I removed that whole section and compiled without a problem 😄 .. got data I needed I returned release 3.1.1. 🙂 ..
I moved to 2020 myself for few projects and so far did not notice any issues