On 01/13/2015 11:45 AM, Stefan Monnier wrote:
> IOW it is*not*  a const function.

To fix this I installed the attached patch as master commit 
785adfcc8dee02ac544f80e4f7f8d3d5b2965981 
<http://git.savannah.gnu.org/cgit/emacs.git/commit/?id=785adfcc8dee02ac544f80e4f7f8d3d5b2965981>. 
It's not pretty, but at least we're no longer lying to the compiler.