See tracker bug.
Well glibc is a bit of a special case since it needs to do "manual" stripping (and the ebuild accordingly declares RESTRICT=strip).
We will need to copy / adopt the logic somehow.
Let's fix this a while after EAPI=7 can be used in the stable tree. Depends on "dostrip".
(In reply to Michał Górny from comment #3)
Toolchain follows the same rules as Base for EAPIs.