Fix ffmpeg build

ffmpeg/Makefile

@@ -35,6 +35,9 @@ ubuntu2204:
 	bash ../ubuntu2204.sh chown $$(id -u):$$(id -g) . -R  # fix permissions
 
 ffmpeg_impl:
+	# see issue https://exerror.com/fatal-detected-dubious-ownership-in-repository/
+	git config --global --add safe.directory '*'
+
 	apt-get update
 	sudo apt-get install -y yasm
 	sudo apt-get install -y nasm # apparently x264 switched to this