Coverity and build chain fixes from Nelson

Coverity and build chain fixes from Nelson

* merges:
  Coverity: Resource leak: CID 400015
  Fix configure.ac
  Fix configure
  xstrncpy saga
  xstrncpy saga
  xstrncpy saga
  Fix tty build broken in last configure.ac changes
  Do not add tty objects when no tty is available
  Coverity: CID 400005: Division or modulo by zero
  Coverity: CID 400006: Division or modulo by zero
  Coverity: Out of bounds write: CID 21140
  Coverity: CID 400012 Overrun dynamic
  Fix build for branches without tags
  Coverity CID 400013 Printf arg type mismatch
  Coverity: CID 400031: Tainted string
  Coverity: CID 400829: Uninit
  Use dup2 if available for -t. Also check for ttyname and isatty in configure.
  Coverity: CID 400828 Resource leak
  Use AS_IF instead of if some places - be more M4sh friendly
  Update copyright, remove unused ent arguments