Stop excluding the dyn way for the dph packages on Windows

Now that we can build the GHC package the dyn way, there's no need
to exclude them.

ghc.mk

@@ -565,18 +565,6 @@ $(error Unknown integer library: $(INTEGER_LIBRARY))
 endif
 endif
 
-# ----------------------------------------
-# Workarounds for problems building DLLs on Windows
-
-ifeq "$(TargetOS_CPP)" "mingw32"
-# We don't build the GHC package the dyn way on Windows, so
-# we can't build these packages the dyn way either. See trac #5987
-libraries/dph/dph-lifted-base_dist-install_EXCLUDED_WAYS := dyn
-libraries/dph/dph-lifted-boxed_dist-install_EXCLUDED_WAYS := dyn
-libraries/dph/dph-lifted-copy_dist-install_EXCLUDED_WAYS := dyn
-libraries/dph/dph-lifted-vseg_dist-install_EXCLUDED_WAYS := dyn
-endif
-
 # -----------------------------------------------------------------------------
 # Include build instructions from all subdirs