security/oidentd: Update to 2.5.1

• FreeBSD 13+ fix (https://github.com/janikrabe/oidentd/commit/cd763e5aebc7f84fff0acad792d3e2a9b0ecdccb)
• Modify Makefile to follow Porter's Handbook more closely
• Define LICENSE_FILE
• Switch to tar.xz release archive
• Remove IPV6 option (it's 2021 not 1999)

Changes https://github.com/janikrabe/oidentd/blob/v2.5.1/NEWS

PR: 256230
Approved by: maintainer timeout