python-utils-r1.eclass: Fix python_optimize to take all of sys.path

Make sure to append NUL to every path in sys.path, rather than using
it as a separator between output entries.  This fixes a bug when
the last path entry was silently discarded, and the function stopped
working with PyPy as a result.

Signed-off-by: Michał Górny <mgorny@gentoo.org>

eclass/python-utils-r1.eclass

@@ -692,7 +692,7 @@ python_optimize() {
 			if [[ ${f} == /* && -d ${D%/}${f} ]]; then
 				set -- "${D%/}${f}" "${@}"
 			fi
-		done < <("${PYTHON}" -c 'import sys; print("\0".join(sys.path))' || die)
+		done < <("${PYTHON}" -c 'import sys; print("".join(x + "\0" for x in sys.path))' || die)
 
 		debug-print "${FUNCNAME}: using sys.path: ${*/%/;}"
 	fi