Patch for PR c/11234

[Zack Weinberg]

"Joseph S. Myers" <jsm@polyomino.org.uk> writes:

> This patch fixes PR c/11234 (nondiagnosis of certain invalid
> conversions between function and object pointers).  Various places
> where GCC itself uses such conversions are changed to use pointers to
> function pointers.
>
> Bootstrapped with no regressions on i686-pc-linux-gnu.  OK to commit
> the patches to except.c, genoutput.c, final.c and recog.h for misuse
> of casts between object and function pointers shown up by this patch,
> and the patches updating weak-6.c and weak-7.c for the new
> diagnostics?

The changes to except.c are OK.  I would prefer that you change the
output field of struct insn_data to a union, and restructure
weak-[67].c so that foo doesn't need to return a pointer to itself.

zw