[Bug debug/88389] -flto -g -gsplit-dwarf is broken

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88389

--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
Mitigated for GCC 8+ by ignoring -gsplit-dwarf with -flto.