First round of amd64 fixes. Compiles and detects BSD partitions, but
may require work for NTFS, NTFS5, or other partitions. There may be more abuse
of "long" on the assumption it were 32 bits, and there may be more endian-
ness assumptions lingering in the code.
Also bump expiration half a year into the future and fix whitespace to make
portlint -C happy. Remove MD5 checksum while at it, and mark MAKE_JOBS_SAFE.
I do not claim maintainership for lack of interest, but possibly this is a
starting point. Also see the FreeBSD-ports discussion this month, and possibly
Debian and/or Fedora have more patches that might be useful.