Change some URLs from author dirs to dist dirs.
The example in the porter's handbook didn't have the trailing slash;
mea culpa for not having caught that when it went in.
Unlike HMAC, which reuses an existing one-way hash function, such as
MD5, SHA-1 or RIPEMD-160, EMAC reuses an existing block cipher to
produce a secure message authentication code (MAC).
WWW: http://search.cpan.org/dist/Digest-DMAC
PR: ports/90550
Submitted by: Gabor Kovesdan
