Add spfval.
Spfval validates SPF records. It does not check them via the network, this was
intentionally omitted in favour of focusing purely on syntactically validating
SPF records. Simply pass the validator a string and it will see if it validates
as an SPFv1 or SPF-Classic record.
If an error is found, it tries its best to report the error in question and the
specific location in the record where the error occured.
WWW: http://spfval.codeshare.ca/
PR: ports/83899
Submitted by: Emanuel Haupt <ehaupt@critical.ch>
