Today I used flag-o-matic to remove fstack-protector gcc flags. But during testing of my ebuild I saw the following message: * test_flag: deprecated, please use test-flags()! The problem was in fstack-flags() function in flag-o-matic.eclass. Thus I've done trivial fix in eclass to replace all occurrences of test_flag on test-flags. BTW. I know you know :). That test_flag() should not be removed from .eclass, as it is used in the tree. xorg-x11-6.8.2-r6.ebuild fex. Patch follows...
Created attachment 77789 [details, diff] Patch for flag-o-matic.eclass. I think it's worth efforts to apply this patch to make the tree a litle bit more clean ;)
I've committed an update to flag-o-matic which should resolve this; re-open if there are still problems.