analysis: Use static functions when possible

It's best to ensure the functions only used in one compilation unit are
marked as static so GCC can inline them if it feels like it.

clutter/clutter-bezier.c

@@ -153,7 +153,7 @@ _clutter_bezier_t2x (const ClutterBezier * b, _FixedT t)
     + b->dx;
 }
 
-gint
+static gint
 _clutter_bezier_t2y (const ClutterBezier * b, _FixedT t)
 {
   /*

clutter/cogl/cogl/cogl-clip-stack.c

@@ -285,7 +285,7 @@ set_clip_planes (float x_1,
     }
 }
 
-void
+static void
 add_stencil_clip_rectangle (float x_1,
                             float y_1,
                             float x_2,

clutter/cogl/cogl/cogl-clip-state.c

@@ -118,7 +118,7 @@ transform_point (CoglMatrix *matrix_mv,
 
 /* Try to push a rectangle given in object coordinates as a rectangle in window
  * coordinates instead of object coordinates */
-gboolean
+static gboolean
 try_pushing_rect_as_window_rect (float x_1,
                                  float y_1,
                                  float x_2,