--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -586,11 +586,11 @@ if(NOT (HAVE_WGL OR HAVE_AGL OR HAVE_CGL
     list(APPEND COIN_TARGET_LINK_LIBRARIES OpenGL::GLX)
   endif()
   set(CMAKE_REQUIRED_LIBRARIES ${COIN_TARGET_LINK_LIBRARIES})
-  check_cxx_source_compiles("
-    #include <GL/gl.h>
-    #include <GL/glx.h>
-    int main() { (void)glXChooseVisual(0L, 0, 0L); glEnd(); return 0; }
-  " HAVE_GLX)
+#  check_cxx_source_compiles("
+#    #include <GL/gl.h>
+#    #include <GL/glx.h>
+#    int main() { (void)glXChooseVisual(0L, 0, 0L); glEnd(); return 0; }
+#  " HAVE_GLX)
 endif()
 
 # Checks specific OpenGL configurations