swrast: Disable glAccum drawing during conditional rendering.

src/mesa/swrast/s_accum.c

@@ -24,6 +24,7 @@
 
 
 #include "main/glheader.h"
+#include "main/condrender.h"
 #include "main/context.h"
 #include "main/macros.h"
 #include "main/imports.h"
@@ -553,6 +554,9 @@ _swrast_Accum(struct gl_context *ctx, GLenum op, GLfloat value)
       return;
    }
 
+   if (!_mesa_check_conditional_render(ctx))
+      return;
+
    swrast_render_start(ctx);
 
    /* Compute region after calling swrast_render_start() so that we know the