CC-BY-NC 4.0 International.
Each .mp file (with the exception of crfuncs.mp) must be run through
mpost.
After this step, the resulting .mps (metapost-flavored encapsulated
postscript) files can either be directly \includegraphics-ed within the
*TeX markup, or each can be converted to a pdf file using mptopdf.
mpost is part of the Metapost CTAN package and available f.e. through
texlive. mptopdf is available through texlive, too.