media-libs/mesa: Add USE flag to enable proprietary codecs

Since https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15258
patent encumbered codes have been disabled as default

Use the chromium flag proprietary-codecs to reenable them for those that
want them

Closes: #25268
Signed-off-by: Mike Lothian <mike@fireburn.co.uk>
Signed-off-by: Matt Turner <mattst88@gentoo.org>

media-libs/mesa/mesa-9999.ebuild

@@ -34,7 +34,8 @@ done
 
 IUSE="${IUSE_VIDEO_CARDS}
 	cpu_flags_x86_sse2 d3d9 debug gles1 +gles2 +llvm
-	lm-sensors opencl osmesa selinux test unwind vaapi valgrind vdpau vulkan
+	lm-sensors opencl osmesa +proprietary-codecs selinux
+	test unwind vaapi valgrind vdpau vulkan
 	vulkan-overlay wayland +X xa xvmc zink +zstd"
 
 REQUIRED_USE="
@@ -434,6 +435,7 @@ multilib_src_configure() {
 		$(meson_feature zstd)
 		$(meson_use cpu_flags_x86_sse2 sse2)
 		-Dvalgrind=$(usex valgrind auto disabled)
+		-Dvideo-codecs=$(usex proprietary-codecs "h264dec,h264enc,h265dec,h265enc,vc1dec" "")
 		-Dgallium-drivers=$(driver_list "${GALLIUM_DRIVERS[*]}")
 		-Dvulkan-drivers=$(driver_list "${VULKAN_DRIVERS[*]}")
 		--buildtype $(usex debug debug plain)

media-libs/mesa/metadata.xml

@@ -17,6 +17,7 @@
 		<flag name="lm-sensors">Enable Gallium HUD lm-sensors support.</flag>
 		<flag name="opencl">Enable the Clover Gallium OpenCL state tracker.</flag>
 		<flag name="osmesa">Build the Mesa library for off-screen rendering.</flag>
+		<flag name="proprietary-codecs">Enable codecs for patent-encumbered audio and video formats.</flag>
 		<flag name="valgrind">Compile in valgrind memory hints</flag>
 		<flag name="vdpau">Enable the VDPAU acceleration interface for the Gallium3D Video Layer.</flag>
 		<flag name="vulkan">Enable Vulkan drivers</flag>