proton: Add gst-libav and ffmpeg to build.

Signed-off-by: Derek Lesho <dlesho@codeweavers.com>

Makefile.in

@@ -53,6 +53,7 @@ include $(SRC)/make/rules-common.mk
 include $(SRC)/make/rules-meson.mk
 include $(SRC)/make/rules-cmake.mk
 include $(SRC)/make/rules-autoconf.mk
+include $(SRC)/make/rules-configure.mk
 include $(SRC)/make/rules-winemaker.mk
 include $(SRC)/make/rules-cargo.mk
 
@@ -351,7 +352,7 @@ $(DIST_FONTS): fonts
 ALL_TARGETS += dist
 GOAL_TARGETS += dist
 
-dist_prefix: wine gst_good
+dist_prefix: wine gst_good gst_libav
 	find $(DST_LIBDIR32)/wine -type f -execdir chmod a-w '{}' '+'
 	find $(DST_LIBDIR64)/wine -type f -execdir chmod a-w '{}' '+'
 	rm -rf $(abspath $(DIST_PREFIX))
@@ -491,6 +492,37 @@ $(eval $(call rules-source,gst_good,$(SRCDIR)/gst-plugins-good))
 $(eval $(call rules-meson,gst_good,32))
 $(eval $(call rules-meson,gst_good,64))
 
+##
+## FFmpeg
+##
+
+FFMPEG_CONFIGURE_ARGS := \
+	--enable-shared \
+	--disable-static \
+	--disable-everything \
+	--disable-programs \
+	--disable-doc \
+
+$(eval $(call rules-source,ffmpeg,$(SRCDIR)/ffmpeg))
+$(eval $(call rules-configure,ffmpeg,32))
+$(eval $(call rules-configure,ffmpeg,64))
+
+## Only use ffmpeg to build gst-libav; we don't ship it.
+$(OBJ)/.ffmpeg-dist32:
+	touch $@
+$(OBJ)/.ffmpeg-dist64:
+	touch $@
+
+##
+## gst-libav
+##
+
+GST_LIBAV_DEPENDS = gst_orc gstreamer gst_base ffmpeg
+
+$(eval $(call rules-source,gst_libav,$(SRCDIR)/gst-libav))
+$(eval $(call rules-meson,gst_libav,32))
+$(eval $(call rules-meson,gst_libav,64))
+
 
 ##
 ## Vulkan-Headers