Here's a patch that adds debuginfod queries for dwz files when they
otherwise cannot be found. It's very similar to the normal debuginfo
lookup code. With this libdebuginfod now hooks into three functions
in gdb: dwarf2_get_dwz_file, open_source_file and elf_symfile_read.
Does anyone know of any code paths that gdb might take when
searching for dwz, source files, or separate DWARF debuginfo that
bypass all of the current libdebuginfod calls?

Aaron