Added SplitObjs for when -split-objs is being used. Removed -split-objs and
-odir from GhcLibHcOpts. -odir shouldn't be needed any more in any case.

Changed order of recursive makes so that recursive make happens before make
in the current directory. This helps when building hslibs as DLLs, where
the cbits DLLs need to be made before the main DLLs.