Xlib in Mac OS?

Hi guise.

I've got a problem with compiling a program in macos: the configure script requires the symbol XOpenDisplay into libX11 (-lX11). After running a nm on all instances of libX11 in the whole system, I found out that there's a _XOpenDisplay symbol for each of them, but no XOpenDisplay.

Is it a sort of wrapper? Can you help me /prog/?

http://developer.apple.com/mac/library/DOCUMENTATION/Darwin/Reference/ManPages/man3/XOpenDisplay.3.html