The $lib output refers to the terminfo database in $out, which is about
10x larger than the ncurses shared library. Splitting these outputs
saves a small amount of space for any derivations that use the terminfo
database but not the ncurses library, but we do not have evidence that
any such exist.
The compiler should not expect to have dynamic versions of all libraries
available, because that configuration doesn't play along nicely with statically
linked libraries.
Fixes https://github.com/NixOS/nixpkgs/issues/6399.
I thought that [1] could be fixed by ensuring that ncurses is available in the
environment (because ghc exports it as a propagateBuildInput), and indeed that
change fixed *some* build failures we've had before. However, the same error
still occurs with other packages, like hledger [2] and Agda [3]. Frankly, I
have no idea why those packages fail and others don't. But clearly the fix was
inadequate, so I'm reverting commit a8076c76.
[1] https://github.com/NixOS/nixpkgs/issues/5616
[2] http://hydra.cryp.to/build/372451/nixlog/1/raw
[2] http://hydra.cryp.to/build/373161/nixlog/1/raw
* There now is full support for building Haskell packages as shared libraries
for GHC versions 7.4.2 or later. The Cabal builder recognizes the following
attributes:
- enableSharedLibraries configures Cabal to build of shared libraries in
addition to static ones. This option requires that all dependencies of
the package have been compiled for use in shared libraries, too.
- enableSharedExecutables configures Cabal to prefer shared libraries when
linking executables.
The default values for these attributes are arguments to the haskellPackages
expression.
* Haskell builds now run in a LANG="en_US.UTF-8" environment to avoid plenty
of build and test suite errors. Without this setting, GHC seems unable to
deal with the UTF-8 character encoding that's generally considered standard
in the Haskell world.
* The Cabal builder supports a new attribute 'testTarget' to specify the exact
set of tests to be run during the check phase.
* The ghc-wrapper attribute ghcVersion has been removed. Instead, we use the
ghc.version attribute, which exists in unwrapped GHC derivations, too.
