multimedia/libde265: Update 1.0.12 => 1.0.16, improve port

Changelogs:
https://github.com/strukturag/libde265/releases/tag/v1.0.13
https://github.com/strukturag/libde265/releases/tag/v1.0.14
https://github.com/strukturag/libde265/releases/tag/v1.0.15
https://github.com/strukturag/libde265/releases/tag/v1.0.16

Improve port:

• Move SDL to option - default on.
• Upstream migrate to SDL2.
• Replace manual STRIP_CMD with INSTALL_TARGET=install-strip.
• Fix warnings from portclippy.
• Optimize armv6/7 handle.
• Regenerate patches.
• Remove upstreamed patches.

Security: CVE-2023-49465
Security: CVE-2023-49467
Security: CVE-2023-49468
MFH: 2025Q4
(cherry picked from commit bdd895f12c1b4c1f35f1b565484006d207562e60)