ref: gl: make g_posenum in alias renderer static

ref/gl/gl_alias.c

@@ -59,7 +59,7 @@ static int	g_used[8192];
 
 // a pose is a single set of vertexes. a frame may be
 // an animating sequence of poses
-int		g_posenum;
+static int	g_posenum;
 
 // the command list holds counts and s/t values that are valid for
 // every frame