Add query for number of ready video frames. #473

Job	Run time
Build windows-latest \|\| SHARED=OFF \|\| PLATFORM=GLFW	28m 32s
Build windows-latest \|\| SHARED=OFF \|\| PLATFORM=libretro	32m 25s
Build windows-latest \|\| SHARED=OFF \|\| PLATFORM=KHR_DISPLAY	31m 0s
Build windows-latest \|\| SHARED=ON \|\| PLATFORM=GLFW	31m 47s
Build windows-latest \|\| SHARED=ON \|\| PLATFORM=libretro	27m 3s
Build windows-latest \|\| SHARED=ON \|\| PLATFORM=KHR_DISPLAY	30m 4s
Build ubuntu-latest \|\| SHARED=OFF \|\| PLATFORM=GLFW	25m 56s
Build ubuntu-latest \|\| SHARED=OFF \|\| PLATFORM=libretro	26m 21s
Build ubuntu-latest \|\| SHARED=OFF \|\| PLATFORM=KHR_DISPLAY	25m 56s
Build ubuntu-latest \|\| SHARED=ON \|\| PLATFORM=GLFW	27m 10s
Build ubuntu-latest \|\| SHARED=ON \|\| PLATFORM=libretro	25m 3s
Build ubuntu-latest \|\| SHARED=ON \|\| PLATFORM=KHR_DISPLAY	27m 3s
	5h 38m 20s

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