Fix typos

Closes #1402.

examples/boing.c

@@ -302,7 +302,7 @@ void cursor_position_callback( GLFWwindow* window, double x, double y )
  * The Boing ball is sphere in which each facet is a rectangle.
  * Facet colors alternate between red and white.
  * The ball is built by stacking latitudinal circles.  Each circle is composed
- * of a widely-separated set of points, so that each facet is noticably large.
+ * of a widely-separated set of points, so that each facet is noticeably large.
  *****************************************************************************/
 void DrawBoingBall( void )
 {
@@ -446,7 +446,7 @@ void DrawBoingBallBand( GLfloat long_lo,
    static int colorToggle = 0;
 
   /*
-   * Iterate thru the points of a latitude circle.
+   * Iterate through the points of a latitude circle.
    * A latitude circle is a 2D set of X,Z points.
    */
    for ( lat_deg = 0;

src/osmesa_context.c

@@ -240,7 +240,7 @@ GLFWbool _glfwCreateContextOSMesa(_GLFWwindow* window,
         if (ctxconfig->forward)
         {
             _glfwInputError(GLFW_VERSION_UNAVAILABLE,
-                            "OSMesa: Foward-compatible contexts not supported");
+                            "OSMesa: Forward-compatible contexts not supported");
             return GLFW_FALSE;
         }