Workaround "Function... not defined in.." (breakpoints not found) (GDB bug)
This is a rework of the fix from CI branch !256 (closed), corrected such that it should work with all versions of gdb from and including the one shipped on Ubuntu 18.04. The 18.04 tests still fail due to, what seems to be, another unrelated GDB bug.
The problem that this fixes:
Function "_Z13do_breakpointIN4tmwa3map11script_dataEEvRKT_PKc" not defined in "/builds/specing/tmwa/src/debug-debug/map-script-persist.cpp".