r300: Call radeonSetCliprects from radeonMakeCurrent.

Based on a patch by Panagiotis Papadakos.

Among other things, this makes sure the framebuffer object associated with the
drawable has the correct size when _mesa_make_current is called, so the default
viewport is set up correctly.

Also update radeon->lastStamp in radeonSetCliprects.

src/mesa/drivers/dri/r300/radeon_context.c

@@ -51,6 +51,7 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #include "radeon_macros.h"
 #include "radeon_reg.h"
 
+#include "radeon_state.h"
 #include "r300_state.h"
 
 #include "utils.h"
@@ -279,6 +280,8 @@ GLboolean radeonMakeCurrent(__DRIcontextPrivate * driContextPriv,
 
 			r300UpdateWindow(radeon->glCtx);
 			r300UpdateViewportOffset(radeon->glCtx);
+
+			radeonSetCliprects(radeon);
 		}
 
 		_mesa_make_current(radeon->glCtx,

src/mesa/drivers/dri/r300/radeon_lock.c

@@ -90,7 +90,6 @@ static void r300RegainedLock(radeonContextPtr radeon)
 #else
 		radeonUpdateScissor(radeon->glCtx);
 #endif
-		radeon->lastStamp = drawable->lastStamp;
 	}
 
 	if (sarea->ctx_owner != radeon->dri.hwContext) {

src/mesa/drivers/dri/r300/radeon_state.c

@@ -185,6 +185,8 @@ void radeonSetCliprects(radeonContextPtr radeon)
 
 	if (radeon->state.scissor.enabled)
 		radeonRecalcScissorRects(radeon);
+
+	radeon->lastStamp = drawable->lastStamp;
 }