[PATCH] Fix libstdc++ usage of __ctype_b/__ctype_to*

[Roland McGrath]

I haven't found anything that actually describes the bug being tested for.
>From looking at the test, I presume it is a crash because the test does
not examine the results of anything it does.  If you are happy enough with
explicit version checks and safe presumptions rather than precise empirical
feature/bug tests, then checking for glibc 2.3 is easy enough.  That is,
if __GLIBC__ == 2 && __GLIBC_MINOR__ == 2 do the current test.  If 
__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 3) then skip the
AC_TRY_RUN test and presume it works.