Currently media-video/binkplayer only depends on ~virtual/libstdc++-3.3 if you have USE="x86", and on emul-x86-* if amd64, which is completely wrong since /usr/lib32/libstdc++.so.5 is always provided by sys-libs/libstdc++-v3 (with multilib useflag). Please correct it.
It deps on app-emulation/emul-linux-x86-compat which deps on sys-libs/libstdc++-v3 so it's correct as is...
Please, elaborate what you want use to correct and reopen bug. As it is it should work.