$NetBSD$

In case where both QT4 and Common plugins are enabled, VapourSynth is included
twice.

--- avidemux_plugins/CMakeLists.txt.orig	2022-09-17 13:59:17.000000000 +0000
+++ avidemux_plugins/CMakeLists.txt
@@ -267,7 +267,9 @@ ENDIF(DO_COMMON)
 ADD_SUBDIRECTORY(ADM_videoEncoder)
 ADD_SUBDIRECTORY(ADM_videoFilters6)
 IF(DO_QT4)
-        add_subdirectory(ADM_demuxers/VapourSynth)
+	IF(NOT DO_COMMON)
+		add_subdirectory(ADM_demuxers/VapourSynth)
+	ENDIF(NOT DO_COMMON)
     #    add_subdirectory(ADM_scriptEngines)
         #IF(USE_OPENGL AND NOT WIN32)
         IF(USE_OPENGL )