[Driver] Bring back "Clean up Debian multiarch /usr/include/<triplet> madness" and restore i586-linux-gnu
This reverts commit 933d146f38c6d77a9b4fdde2b6b394f6ad9f8bf5 and 21b211a8f24f8ecfab8b380ff761a90d9cf73924
(which mis-identified the issue) but restores i586-linux-gnu which was
removed by Gnu.cpp: remove obsoleted i386 triple detection from end-of-life distribution versions.
Looks like i586-linux-gnu was not dead enough (used in a sysroot by Fuchsia build bot based on Debian jessie:)
but i486-linux-gnu should be very dead by now.