https://bugs.gentoo.org/728566
http://ffmpeg.org/pipermail/ffmpeg-devel/2020-February/257474.html

--- a/libswscale/x86/yuv2rgb.c
+++ b/libswscale/x86/yuv2rgb.c
@@ -83,6 +83,7 @@ av_cold SwsFunc ff_yuv2rgb_init_x86(SwsContext *c)
 #if HAVE_X86ASM
     int cpu_flags = av_get_cpu_flags();
 
+#if HAVE_SSSE3
     if (EXTERNAL_SSSE3(cpu_flags)) {
         switch (c->dstFormat) {
         case AV_PIX_FMT_RGB32:
@@ -111,6 +112,7 @@ av_cold SwsFunc ff_yuv2rgb_init_x86(SwsContext *c)
             return yuv420_rgb15_ssse3;
         }
     }
+#endif
 
     if (EXTERNAL_MMXEXT(cpu_flags)) {
         switch (c->dstFormat) {