ftp://ftp.informatik.rwth-aachen.de/pub/mirror/FreeBSD/development/FreeBSD-CVS/src/contrib/libstdc++/config/os/  direct

[DIR]aix/  direct  1000+ twin directories
[DIR]bsd/  direct  900+ twin directories
[DIR]generic/  direct  1000+ twin directories
[DIR]djgpp/  direct  750+ twin directories
[DIR]mingw32/  direct  540+ twin directories
[DIR]gnu-linux/  direct  152 twin directories
[DIR]hpux/  direct  950+ twin directories
[DIR]irix/  direct  570+ twin directories
[DIR]newlib/  direct  590+ twin directories
[DIR]solaris/  direct  1000+ twin directories
[DIR]uclibc/  direct  540+ twin directories
[DIR]vxworks/  direct  137 twin directories
[DIR]tpf/  direct  117 twin directories
[DIR]osf/  direct  82 twin directories
[DIR]qnx/  direct  580+ twin directories
[DIR]windiss/  direct  148 twin directories