on one host, I always have problems building (with osc build) packages like
xmobar and xmonad that use ghc.

the build fails with
ghc --make -no-user-package-db Setup
/usr/lib64/ghc-8.0.1/package.conf.d/package.cache: openBinaryFile: does not
exist (No such file or directory)

and this is likely related to the build.log having multiple instances of
 /usr/lib64/ghc-8.0.1/bin/ghc-pkg: error while loading shared libraries:
libHSterminfo-0.4.0.2-ghc8.0.1.so: cannot open shared object file: No such file
or directory

even though ghc-terminfo was installed before that point,
but since it does not have a %post section calling ldconfig
the library could not be found by the dynamic linker.

interestingly, on another host, I dont have that problem,
so it might depend on the host's version of osc, build or kernel
or random timing/ordering, so that sometimes another lib gets installed between
ghc-terminfo and its user and that calls ldconfig.


IMHO, all of ghc's subpackages containing .so files
should call ldconfig in %post