@QA, radhermit would like to have some semi-official spec for this before implementing, so I'd like to discuss it here. The idea is that some flags are not supposed to be depended upon. For example, some Python packages provide convenience flags for user that pull in optional runtime deps. However, other packages aren't supposed to depend on those flags but instead pull in the appropriate dependencies themselves. Therefore, I'd like to introduce a variable (say, QA_IUSE_NO_USEDEP) that specifies which flags are not supposed to be depended upon, and have pkgcheck/repoman trigger QA warnings when other packages actually depend on them.
