- platforms other than NetBSD (Linux, and FreeBSD)?

  PFKEYV2 and XFRM are pretty esoteric.

  Libreswan builds on Fedora, Debian, Apline (they each
  have their own packaing quirks), FreeBSD, NetBSD, OpenBSD

  not sure about this package

- add following entries to pkg-vulnerabilities

libreswan<5.0rc3	denial-of-service	https://libreswan.org/security/CVE-2024-3652/CVE-2024-3652.txt
libreswan<5.0rc2	denial-of-service	https://libreswan.org/security/CVE-2024-2357/CVE-2024-2357.txt

libreswan<4.15		denial-of-service	https://libreswan.org/security/CVE-2024-3652/CVE-2024-3652.txt
libreswan<4.13nb1	denial-of-service	https://libreswan.org/security/CVE-2024-2357/CVE-2024-2357.txt
libreswan<4.12nb1	denial-of-service	https://libreswan.org/security/CVE-2023-38712/CVE-2023-38712.txt
libreswan<4.12nb1	denial-of-service	https://libreswan.org/security/CVE-2023-38711/CVE-2023-38711.txt
libreswan<4.12nb1	denial-of-service	https://libreswan.org/security/CVE-2023-38710/CVE-2023-38710.txt
libreswan<4.9nb3	denial-of-service	https://libreswan.org/security/CVE-2023-30570/CVE-2023-30570.txt
libreswan<4.9nb2	denial-of-service	https://libreswan.org/security/CVE-2023-23009/CVE-2023-23009.txt
libreswan<4.6		denial-of-service	https://libreswan.org/security/CVE-2022-23094/CVE-2022-23094.txt

Notes:

4.7		earliest pkgsrc version, 4.6 is just a baseline
CVE-2023-2295	was a bug in Red Hat's Libreswan package, not Libreswan
4.9nb2 4.9nb3	were cut from libreswan's mainline