linux-capture: Mark captures as custom drawn

The linux window and monitor captures draw in a custom way, therefore
they must be marked as types of sources that do custom rendering.

plugins/linux-capture/xcomposite-main.cpp

@@ -69,7 +69,8 @@ extern "C" void xcomposite_load(void)
 	memset(&sinfo, 0, sizeof(obs_source_info));
 
 	sinfo.id = "xcomposite_input";
-	sinfo.output_flags = OBS_SOURCE_VIDEO;
+	sinfo.output_flags = OBS_SOURCE_VIDEO |
+	                     OBS_SOURCE_CUSTOM_DRAW;
 
 	sinfo.get_name       = xcompcap_getname;
 	sinfo.create         = xcompcap_create;

plugins/linux-capture/xshm-input.c

@@ -467,7 +467,8 @@ static uint32_t xshm_getheight(void *vptr)
 struct obs_source_info xshm_input = {
 	.id             = "xshm_input",
 	.type           = OBS_SOURCE_TYPE_INPUT,
-	.output_flags   = OBS_SOURCE_VIDEO,
+	.output_flags   = OBS_SOURCE_VIDEO |
+	                  OBS_SOURCE_CUSTOM_DRAW,
 	.get_name       = xshm_getname,
 	.create         = xshm_create,
 	.destroy        = xshm_destroy,