haskell-cabal.eclass: distinct between package-local breakages and system-wide

Limit output of 'ghc-pkg check' by 20 lines.

Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
dev-vcs/darcs: backport tests building on ghc-7.8

Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
nicer to have the #define and #include on separate lines, so add \n in the sed in cairo workaround
Add back the S to gtk-0.12.5.7.3