The checksum programs have been extended to emulate GNU behavior when invoked with the name ending in "sum".
Some ports do fail now (e.g. print/qpdf) since they try to use "sha256sum -c <chksumsfile>" and abort the configure phase if that command fails.
The sha256sum fails with error status due to "-c" not being implemented in GNU emulation mode.
The attached patch adds support for checksum verification as performed by the GNU sha256sum program (and of course also for the other hash algorithms supported).