configure failure with v2.1.0 and 2.1.1

[Robin Cook <rcook wyrms net>]

I am getting the following error when trying to compile gtk+ v2.1.0 or 
2.1.1.  gtk+ 2.0.6 configures and compiles without a problem.

I have fontconfig, Xft2, Xft1, Xrender installed.


/* Override any gcc2 internal prototype to avoid an error.  */
#ifdef __cplusplus
extern "C"
#endif
/* We use char because int might match the return type of a gcc2
   builtin and then its argument prototype would still apply.  */
char XOpenDisplay ();
#ifdef F77_DUMMY_MAIN
#  ifdef __cplusplus
     extern "C"
#  endif
   int F77_DUMMY_MAIN() { return 1; }
#endif
int
main ()
{
XOpenDisplay ();
  ;
  return 0;
}
configure:15945: result: no
configure:15950: error: *** libX11 not found. Check 'config.log' for 
more details.