I've downloaded the comport and pmpd libraries and compiled them but Pd can't create these objects. In /usr/local/lib/pd/extra there is a directory for each library and in each directory there's a .pd_linux but Pd just can't create them. There are some files with a .o extension that I don't see in other libraries (e.g. iemmatrix or zexy), don't know if that's an issue.