The first commit fixes the fact that make install doesn't create PARROT_LIBRARY_DIR. This is a problem when someone (like me) uses DESTDIR to allow for clean install/removal. (Yay stow!)
The second one removes NQP_LANGUAGE_DIR which doesn't seem to be used anywhere. Feel free to drop this one if it serves some purpose I can't see.
[install] Create all directories before use
This mostly matters if someone is using DESTDIR
[Makefile] Remove NQP_LANG_DIR variable
It doesn't seem to be used anywhere.