> I suppose the explicit check for stdint.h is not necessary and you need to
> cover for the case where inttypes.h provides the required definition.  See
> the autoconf manual which says
>
>   -- Macro: AC_TYPE_INTPTR_T
>       If `stdint.h' or `inttypes.h' defines the type `intptr_t', define
>       `HAVE_INTPTR_T'.  Otherwise, define `intptr_t' to a signed integer
>       type wide enough to hold a pointer, if such a type exists.
>
> I don't know what the canonical header inclusion case to use would be
> though.  Maybe Ralf knows.

Since we now use Autoconf 2.64, you could also try the attached 
rewritten stdint.m4.

  stdint.m4 |  510 ++++--------------------------------------------------
  1 file changed, 39 insertions(+), 471 deletions(-)

:-)

You can use GCC_STDINT_TYPES (new in this version) instead of 
GCC_HEADER_STDINT since GCC does not need int_leastNN_t and int_fastNN_t.

Bonus points for using GCC_STDINT_TYPES elsewhere in the tree.

Paolo