This function is missing on some platforms:
Minix 3.1.8, AIX 4.3.2, IRIX 6.5, Solaris 11 2010-11, Cygwin, mingw, MSVC 9, Interix 3.5, BeOS.
On platforms where off_t is a 32-bit type, this function may not
work correctly on huge directories larger than 2 GB. The fix is to use
the AC_SYS_LARGEFILE macro.