It looks like csky was created by copying & pasting the m68k port,
but m68k-specific stuff was left over related to target selection.
The makefile doesn't do anything with it, so punt it all to make
the file much simpler.
Depending on the processing order of rules when installing in parallel,
these install rules might be processed before some other rule happens
to create the respective dirs. Make sure each one creates the needed
dirs before installing into them.