x11-fonts/fontconfig: update to 2.17.1

Release notes:

• https://www.freedesktop.org/software/fontconfig/release/ChangeLog-2.16.0
• https://gitlab.freedesktop.org/fontconfig/fontconfig/-/releases#2170-2025-06-27

Port changes:

• Sort MESON_ARGS
• Fix NLS option
• Drop local fclang patch

PR: 285426
Summitted by: diizzy
Exp-run by: antoine