work around a problem where fp registers get corrupted (DO NOT MERGE)

// Rendering

///////////////////////////////////////////////////////////////////////////////

Rect* gHackDontCorruptRegisters;

void LayerRenderer::prepareDirty(float left, float top, float right, float bottom, bool opaque) {

    LAYER_RENDERER_LOGD("Rendering into layer, fbo = %d", mLayer->getFbo());

    Rect dirty(left, top, right, bottom);

    gHackDontCorruptRegisters = &dirty;

    glBindFramebuffer(GL_FRAMEBUFFER, mLayer->getFbo());

    const float width = mLayer->layer.getWidth();

    const float height = mLayer->layer.getHeight();

#if RENDER_LAYERS_AS_REGIONS

    Rect dirty(left, top, right, bottom);

    if (dirty.isEmpty() || (dirty.left <= 0 && dirty.top <= 0 &&

            dirty.right >= width && dirty.bottom >= height)) {

        mLayer->region.clear();