Portage has such a "FEATURE": compressdebug Compress the debug sections in the split debug files with zlib to save space. Make sure you have built both binutils and gdb with USE=zlib support for this to work. See splitdebug for general split debug information (upon which this feature depends).
which can be considered esp. if we're perhaps going to use -ggdb. (By the way, I wonder if it'll be enough to make Chromium compile with -ggdb on x86, which is problematic. Probably this option doesn't change anything about this because the linker would still need the same amount of memory during linking, I think.)