needs -Accflags=-fuse-ld=gold
for now with dwp only. non-linux platforms need llvm-dwp or such.
recommended: -Doptimize="-gdwarf-5 -g3 -fvar-tracking-assignments"
See https://gcc.gnu.org/wiki/DebugFission
todo: gdb 8.1 Dwarf Error: wrong unit_type in compilation unit header (is 4, should be 1 or 2)