error in configuration

[Mohamed Aser <mohasr at link dot net>]

while i'm configuring a program in kde3 that happen:

$ ./configure
it gave me this error 
checking for X... configure: error: Can't find X includes. Please check your installation and add the correct paths!

and in config.log this is the last part of it:
=====================================
configure:5176: checking for X
configure:5215: gcc -E  conftest.c >/dev/null 2>conftest.out
configure:5211:27: X11/Intrinsic.h: No such file or directory
configure: failed program was:
#line 5210 "configure"
#include "confdefs.h"
#include <X11/Intrinsic.h>
configure:5291: gcc -o conftest -O2     conftest.c -lXt  1>&5
/usr/bin/ld: cannot find -lXt
collect2: ld returned 1 exit status
configure: failed program was:
#line 5284 "configure"
#include "confdefs.h"

int main() {
XtMalloc()
; return 0; }
=====================================
what showld i do now ?!?