multimedia/ffmpeg: update to 8.0.1

• fix XCB option [1]
• add a nox11 flavor [2]
• detect breakage in symbol versionning detection [3]
• incorporate a chromium patch to readd av_stream_get_first_dts() necessary to unbundle ffmpeg in chromium distributions like qt*-webengine. as of today chromium devs has not found a way to avoid using this function so they keep readding this function in their bundled version of ffmpeg.

PR: 290246 [1]
PR: 278705 [2]
PR: 291868 [3]