Add winmm to libraries for RTS under Windows, where it's now used for
threadDelay.
then [ clibdir ]
else [ ghc_src_dir cGHC_RUNTIME_DIR ],
hs_libraries = [ "HSrts" ],
+#ifndef mingw32_TARGET_OS
extra_libraries = [],
+#else
+ extra_libraries = [ "-lwinmm" ], -- for the threadDelay timer
+#endif
include_dirs = if installing
then [ clibdir ++ "/includes" ]
else [ ghc_src_dir cGHC_INCLUDE_DIR ],