X11 includes and libraries path configuration

[Gabriel Antonio Arcos Acosta]

Hi all !!

I have installed xfree binaries on cygwin, and I try to compile a simple
piece of code:

#include <X11/Intrinsic.h>

int main()
{ return 0;}

and the compiler fail, becouse it can find the file Intrinsic.h

Actually the file is in /usr/X11R6/include

what enviroment variable I have to set to the compiler can find it? and what
is the variable to the linker can find the X11 libraries?