makefile
fix directory specified in make uninstall
makefile: rmdir portability

i think bsd has rmdir -p but not rmdir --parents. gnu supports both.
fix directory name in make uninstall
make uninstall: fix (probably) failed rmdir

mkdir -p fails if any of the directory components is not empty.
extract bin and lib directories
make install: mkdir before install
make uninstall: rmdirs