openat on 10.6.8?

[raf]

Hi,

I just tried to compile (/usr/bin/cc) something (not a
port) that uses openat(2) on 10.6.8 (with current
macports and Xcode 3.2.6 (1761)) but it wasn't there. I
expected it to be, because openat() was standardized by
2008 and the 10.6.8 system is from 2010. Did I compile
it wrong (e.g., old default compiler), or did openat()
just not appear until a later version of macOS?

cheers,
raf