opengl: ensure the gl provider is imported before window creation

+ export the print gl version to be called after window creation

kivy/core/gl/__init__.py

@@ -19,7 +19,6 @@ if gl_check.lower() in ['0', 'false', 'no']:
 # Automaticly import window auto to ensure the default window creation
 import kivy.core.window
 
-# Display the current OpenGL version
+def print_gl_version():
     version = glGetString(GL_VERSION)
     Logger.info('GL: OpenGL version <%s>' % str(version))
-

kivy/core/window/__init__.py

@@ -154,6 +154,9 @@ class WindowBase(EventDispatcher):
         if Config.getboolean('kivy', 'show_fps'):
             self.show_fps = True
 
+        # before creating the window
+        import kivy.core.gl
+
         # configure the window
         self.create_window(params)
 
@@ -181,7 +184,8 @@ class WindowBase(EventDispatcher):
 
     def create_window(self, params):
         '''Will create the main window and configure it'''
-        pass
+        from kivy.core.gl import print_gl_version
+        print_gl_version()
 
     def on_flip(self):
         '''Flip between buffers (event)'''