Compiling ghc on one of my systems takes way too long and too much resources, which is why I was using the binary flag. Said flag appears to be missing from the latest stable version of ghc, ghc-6.8.2-r1. Reproducible: Always Steps to Reproduce: 1. Install ghc-6.8.2 with binary use flag enabled, and wait 10 minutes. 2. Upgrade to ghc-6.8.2-r1, and wait 6+ hours. Actual Results: A wait that seems to be longer than an eternity. Expected Results: A quick install.
Read the ChangeLog for dev-lang/ghc; 17 Apr 2009; Lennart Kolmodin <kolmodin@gentoo.org> +ghc-6.8.2-r1.ebuild: Add a restricted version of ghc 6.8.2 (-r1), but that can handle >=sys-libs/readline-6. Previous ghc versions depends on =readline-5, which gives problems now that readline-6 is in the tree. To allow other readline versions we have bundled a precompiled readline-5 package, making the ghc bootstrap process work. Thus, this also forced us to remove the USE=binary flag. See bug #259867. And also, why not use ghc-6.10.4? Except for still being keyworded, it is better in every other way.
And wait two days for it to install? I'd rather remove ghc and darcs.
If you absolutely want to, ghc-6.10.4 supports USE=binary. So far we've got binaries for x86, amd64, sparc and ppc64.