The PR is for a C++ form of the form

const double val() const { ... }

where the warning location is at the second const (by accident, in 
reality it's just past the function's declarator), while the first const 
is the one that we are warning about.

This patch adds some logic to the C and C++ frontends to look for the 
qualifier, or a typedef name, and point the warning there. C needs a 
little more work because the ignored qualifier could also be an address 
space.

Bootstrapped and tested on x86_64-linux (a while ago, will retest). Ok 
for trunk?


Bernd