Index: nglib/CMakeLists.txt
--- nglib/CMakeLists.txt.orig
+++ nglib/CMakeLists.txt
@@ -11,7 +11,7 @@ if(EMSCRIPTEN)
   target_include_directories(nglib PUBLIC $<TARGET_PROPERTY:ngcore,INTERFACE_INCLUDE_DIRECTORIES>)
 else(EMSCRIPTEN)
   target_link_libraries(nglib PUBLIC ngcore)
-  target_link_libraries( nglib PRIVATE ${CMAKE_THREAD_LIBS_INIT} ${JPEG_LIBRARIES} ${MKL_LIBRARIES} ${ZLIB_LIBRARIES} occ_libs netgen_cgns )
+  target_link_libraries( nglib PRIVATE ${CMAKE_THREAD_LIBS_INIT} ${JPEG_LIBRARIES} ${MKL_LIBRARIES} ${ZLIB_LIBRARIES} occ_libs netgen_cgns -L/usr/X11R6/lib)
 endif(EMSCRIPTEN)
 
 install(TARGETS nglib netgen_cgns ${NG_INSTALL_DIR})
