n4.3.9
swscale/arm: add yuv2planeX_8_neon
swscale/arm: add ff_hscale_8_to_15_neon
arm: swscale: Only compile the rgb2yuv asm if .dn aliases are supported
fix build with gas-preprocessor.pl
swscale: arm: fix NEON hscale init
swscale/arm/yuv2rgb: make the code bitexact with its aarch64 counter part