@lexszero интересно, у меня такого пакета вообще нету. Но и да, я не понял, как это решает проблему одновременно установленных нескольких инстансов ghc в системе?
@lexszero -# emerge -av '=dev-lang/ghc-7.6.3-r1:0/7.6.3'
Calculating dependencies... done!
[ebuild UD ] dev-lang/ghc-7.6.3-r1:0/7.6.3::gentoo [7.8.4:0/7.8.4::gentoo] USE="ghcbootstrap ghcmakebinary gmp -binary -doc -llvm%" 0 KiB
Total: 1 package (1 downgrade), Size of downloads: 0 KiB
!!! Multiple package instances within a single package slot have been pulled
!!! into the dependency graph, resulting in a slot conflict:
dev-lang/ghc:0
(dev-lang/ghc-7.6.3-r1:0/7.6.3::gentoo, ebuild scheduled for merge) pulled in by
=dev-lang/ghc-7.6.3-r1:0/7.6.3 (Argument)
(dev-lang/ghc-7.8.4:0/7.8.4::gentoo, installed) pulled in by
>=dev-lang/ghc-7.8.3:0/7.8.4= required by (dev-haskell/haskell-platform-2014.2.0.0:0/2014.2.0.0::gentoo, installed)
^^ ^^^^^^^^^^^^^^
>=dev-lang/ghc-6.10.4:0/7.8.4= required by (dev-haskell/extensible-exceptions-0.1.1.4:0/0.1.1.4::gentoo, installed)
^^^^^^^^^
(and 48 more with the same problems)