Fixes <https://bugs.gnu.org/30100>.
Regression introduced in 667082d591.
Reported by Leo Famulari <leo@famulari.name>.
* gnu/packages/haskell.scm (ghc)[arguments] <configure-bin>: Adjust to
correctly determine the extension of "libncursesw.so.X.Y".
* gnu/packages/haskell.scm (ghc-fingertree)[arguments]: Delete to run tests.
[native-inputs]: Add ghc-hunit, ghc-quickcheck, ghc-test-framework,
ghc-test-framework-hunit, and ghc-test-framework-quickcheck2.
* gnu/packages/haskell.scm (ghc-exceptions)[arguments]: Delete to run tests.
[native-inputs]: Add ghc-test-framework and ghc-test-framework-quickcheck2.
* gnu/packages/haskell.scm (ghc-cmark): Update to 0.5.6.
[description]: Update version information about bundled libcmark, and move
it to a source comment.
