I am trying to install sage from overlay sage-on-gentoo. However, I get this mask:

• dev-libs/mpc-1.0.2::gentoo (masked by: package.mask)
  /usr/portage/profiles/package.mask/funtoo-cautionary:

1. Oleg Vinichenko (19 Apr 2013)
2. mask back mpc-1.0.1, ebuild itself is fine and usable
3. the mask required for metro stages successfully built until
4. we implement newer gcc ebuilds, see FL-507

• dev-libs/mpc-1.0.1::gentoo (masked by: package.mask)

It seems that FL-507 is already resolved, but this mask still exists. Is it safe to unmask that?