Enable neon instructions on linux/armv7 for ffmpeg builder.

builders/ffmpeg.cmake

@@ -148,6 +148,11 @@ else()
 		else()
 			set(FFMPEG_TARGET_OS "linux")
 			lcb_configure_options("--enable-runtime-cpudetect")
+			if(CMAKE_SYSTEM_PROCESSOR MATCHES "armv7")
+				lcb_configure_options("--cpu=cortex-a8")
+				lcb_extra_cflags("-mfpu=neon")
+				lcb_extra_cxxflags("-mfpu=neon")
+			endif()
 		endif()
 		lcb_configure_options("--cc=$CC")
 	endif()