See summary. Since we don't have a use.force in profiles, this needs to be worked around at the ebuild level, possibly by changing to a termcap-compat flag that can be use.masked and inverting the use logic.
Created attachment 59850 [details, diff] vim.eclass-termcap-use.flag-93970.patch Please test, because I'm too lazy to do it myself. Apply this to the eclass, then copy {vim,gvim,vim-core}-6.3.074 to -r1. Assuming it works, you'll need to use.mask termcap-compat on *bsd. This'll also affect vim7, but it's in p.mask so we don't really care.
6.3.075, thanks