Currently, we build the Haskell unittests with custom GHC flags,
because we (I) were quite lazy when initially writing the
unittests. This is not a problem for the tests themselves, but it
creates problem when (for example) one would want to pass all
$(HS_LIB_SRCS) to the compilers; this is not doable unless we
"degrade" the flags used for all modules, instead of just for QC.hs.

So we do two things to fix this:

- first, we go and add type declaration to all functions that were
  missing them (in QC), and fix the couple of cases of monomorphism
  restrictions; this gets us rid of -fno-warn-missing-signature and
  -fno-warn-monomorphism-restriction
- then, we move the actually important remaining options
  (-fno-warn-orphans and -fno-warn-unused-imports; see the explanation
  for the latter in the newly added FIXME) to a compiler pragma in the
  file, so that when building the unittests only this file is using
  the extra options

And finally we can then drop the other unused options
(-fno-warn-missing-methods anmd -Wwarn), leaving htools/test use
simply -fhpc. This is more in-line with the other files, and thus we
can handle all of HS_LIB_SRCS the same.

Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: René Nussbaumer <rn@google.com>