+_mesa_readbuffer(struct gl_context *ctx, struct gl_framebuffer *fb,
+ GLenum buffer, gl_buffer_index bufferIndex);
+
+extern void
+_mesa_update_draw_buffers(struct gl_context *ctx);
+
+extern GLenum
+_mesa_back_to_front_if_single_buffered(const struct gl_framebuffer *fb,
+ GLenum buffer);
+
+void GLAPIENTRY
+_mesa_ReadBuffer_no_error(GLenum mode);