Add libav, avplay, and qt_avplay

Imported from the genode repository.

Issue genodelabs/genode#3103

ports/libav.hash

@@ -0,0 +1 @@
+453c3394e14101acc88735246488d154380735ed

ports/libav.port

@@ -0,0 +1,22 @@
+LICENSE   := GPLv3
+VERSION   := 11.6
+DOWNLOADS := libav.archive
+
+URL(libav) := https://www.libav.org/releases/libav-$(VERSION).tar.gz
+SHA(libav) := 4df17921e3b87170d54b738f09241833c618d2173415adf398207b43d27e4b28
+DIR(libav) := src/lib/libav
+SIG(libav) := ${URL(libav)}.asc
+
+PATCHES := src/app/avplay/avplay.patch \
+           src/lib/libav/avcodec.patch
+
+include_subdirs := . libavcodec libavdevice libavfilter libavutil libavformat libswscale \
+                   libavutil/x86 libavutil/arm libavutil/ppc libavcodec/x86 \
+                   libavcodec/arm libavresample
+
+DIRS := $(addprefix include/libav/,$(include_subdirs))
+
+$(foreach dir,$(include_subdirs),\
+          $(eval DIR_CONTENT(include/libav/$(dir)) := src/lib/libav/$(dir)/*.h))
+
+DIR_CONTENT(include/libav/libavutil) += src/lib/libav/libavutil/log2_tab.c