Upgrade oPPUlance (cross compiler for BrainScaleS-2's embedded "PPU" processor)

Initially the build failed due to flex being too old; after upgrading flex another issue came up when building the BrainScaleS version of binutils-gdb (via oppulance) against a modern version of bison → this has been fixed in here.

changed title from Upgrade oPPUlance to Upgrade oPPUlance (cross compiler for BrainScaleS-2's embedded "PPU" processor)

merged

mentioned in commit 7797c195

@emuller the runner was killed but the spawned OKD build job is still running. I'll let you know when it's done.

Thx

@emuller the build was successful, see logs here

@elmath Nice, thx, and it seems to work