diff --git a/source/shared_lib/CMakeLists.txt b/source/shared_lib/CMakeLists.txt
index 8734efb0e..83df8dc29 100644
--- a/source/shared_lib/CMakeLists.txt
+++ b/source/shared_lib/CMakeLists.txt
@@ -111,7 +111,7 @@ IF(BUILD_MODEL_VIEWER OR BUILD_MAP_EDITOR OR BUILD_ZETAGLEST)
 	FIND_PACKAGE(OpenGL REQUIRED)
 	INCLUDE_DIRECTORIES(${OPENGL_INCLUDE_DIR})
 	IF(UNIX)
-		SET(EXTERNAL_LIBS ${EXTERNAL_LIBS} ${OPENGL_LIBRARY})
+		SET(EXTERNAL_LIBS ${EXTERNAL_LIBS} ${OPENGL_LIBRARY} -lX11)
 	ENDIF()
 
 	FIND_PACKAGE(X11 REQUIRED)