This function can be static.
diff --git a/src/video/x11/SDL_x11opengl.c b/src/video/x11/SDL_x11opengl.c
index df6008c..a19d23d 100644
--- a/src/video/x11/SDL_x11opengl.c
+++ b/src/video/x11/SDL_x11opengl.c
@@ -392,7 +392,7 @@ X11_GL_InitExtensions(_THIS)
/* glXChooseVisual and glXChooseFBConfig have some small differences in
* the attribute encoding, it can be chosen with the for_FBConfig parameter.
*/
-int
+static int
X11_GL_GetAttributes(_THIS, Display * display, int screen, int * attribs, int size, Bool for_FBConfig)
{
int i = 0;