win-wasapi: Mark audio outputs as unmonitorable

(Note: This commit also modifies mac-capture and linux-pulseaudio)

This prevents outputs from being monitored, preventing a potential
feedback loop.

plugins/linux-pulseaudio/pulse-input.c

@@ -537,7 +537,8 @@ struct obs_source_info pulse_output_capture = {
 	.id             = "pulse_output_capture",
 	.type           = OBS_SOURCE_TYPE_INPUT,
 	.output_flags   = OBS_SOURCE_AUDIO |
-	                  OBS_SOURCE_DO_NOT_DUPLICATE,
+	                  OBS_SOURCE_DO_NOT_DUPLICATE |
+	                  OBS_SOURCE_DO_NOT_MONITOR,
 	.get_name       = pulse_output_getname,
 	.create         = pulse_create,
 	.destroy        = pulse_destroy,

plugins/mac-capture/mac-audio.c

@@ -797,7 +797,8 @@ struct obs_source_info coreaudio_output_capture_info = {
 	.id             = "coreaudio_output_capture",
 	.type           = OBS_SOURCE_TYPE_INPUT,
 	.output_flags   = OBS_SOURCE_AUDIO |
-	                  OBS_SOURCE_DO_NOT_DUPLICATE,
+	                  OBS_SOURCE_DO_NOT_DUPLICATE |
+	                  OBS_SOURCE_DO_NOT_MONITOR,
 	.get_name       = coreaudio_output_getname,
 	.create         = coreaudio_create_output_capture,
 	.destroy        = coreaudio_destroy,

plugins/win-wasapi/win-wasapi.cpp

@@ -589,7 +589,8 @@ void RegisterWASAPIOutput()
 	info.id              = "wasapi_output_capture";
 	info.type            = OBS_SOURCE_TYPE_INPUT;
 	info.output_flags    = OBS_SOURCE_AUDIO |
-	                       OBS_SOURCE_DO_NOT_DUPLICATE;
+	                       OBS_SOURCE_DO_NOT_DUPLICATE |
+	                       OBS_SOURCE_DO_NOT_MONITOR;
 	info.get_name        = GetWASAPIOutputName;
 	info.create          = CreateWASAPIOutput;
 	info.destroy         = DestroyWASAPISource;