In Fedora, these paths are relative to the debug file itself, so
a better thing to try first. We don't actually have the debug path in
libdw, but we can usually find it from elf->fildes and /proc/self/fd/.
That's even more barfalicious (extreme Linuxism kludgery to paper over
lousy component layering) than the whole abomination of the libdw layer
opening files in the first place.