BUG: Enable large files only if <cstdio> works

Some AIX/gcc version combinations the <cstdio> header breaks when large
file support is enabled.  See this GCC issue for details:

  http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20366

We work around the problem by enhancing the configuration check for
large file support to include <cstdio> when available.  This will cause
LFS to be disabled when the above problem occurs.