Harfbuzz, Nettle, Speex, iconv, libvpx, dvdread updates

The following projects have been updated:

• ffmpeg was updated to 5.1.r107410.
• Harfbuzz was updated to 4.3.0 then 4.4.0 then to 4.4.1.
• Nettle was updated to 3.8.
• Speex was updated to 1.2.1.
• iconv was updated to 1.17.
• libvpx was updated to 1.12.0.
• dvdread was updated to 6.1.3.

Any projects that have a dependency that was updated has also been updated to build with the latest versions of the new libraries as well.