Find SDL2 only if enabled
--- a/avidemux/qt4/CMakeLists.txt
+++ b/avidemux/qt4/CMakeLists.txt
@@ -102,7 +102,7 @@ ENDIF()
 
 # Qt4 openGL
 INCLUDE(admCheckOpenGl)
-IF(NOT APPLE)
+IF(SDL AND NOT APPLE)
   INCLUDE(FindSDL2)
 ENDIF()
 #