Linux: Dual interface meson with BUILD_SINGLE_BINARY

Author: msg7086

VapourSynth/lwlibav_source.c

@@ -31,7 +31,7 @@
 #include <libswscale/swscale.h> /* Colorspace converter */
 
 #include "../common/audio_output.h"
-#ifndef _MSC_VER
+#ifndef BUILD_SINGLE_BINARY
 /* Dummy definitions.
  * Audio resampler/buffer is NOT used at all in this filter. */
 typedef void AVAudioResampleContext;
@@ -65,7 +65,7 @@ uint64_t output_pcm_samples_from_packet(lw_audio_output_handler_t* aohp, AVCodec
 void lw_cleanup_audio_output_handler(lw_audio_output_handler_t* aohp)
 {
 }
-#endif
+#endif // BUILD_SINGLE_BINARY
 
 #include "lsmashsource.h"
 #include "video_output.h"