Log Message:
(DESCR)
  - Add pointer to README
(Makefile)
  - Add SUBST Edit on README and dhisd.h for PREFIX and VARBASE
(Makefile and PLIST)
  - Add one more to install, dhisd.conf.sample
(patch-ab)
  - convert /var to @VARBASE
    (dhisd is expected to run by root, so /var/db is enough.)
Thanks joerg@ and gdt@ for comment.