GHC installs terminfo and haskeline core libraries. We cannot use these libraries in our builds, however, because they have an undeclared dependency on ncurses. Packages that depend on either one of those libraries fail to compile,

Loading package terminfo-0.4.0.0 ... <command line>: can't load .so/.DLL for: libncursesw.so (libncursesw.so: cannot open shared object file: No such file or directory)

..., because ncurses isn't found at build time. This can be solved by patching the installed terminfo package description to add appropriate ncurses paths to the library-dirs and include-dirs stanzas.