nanogui: Thread: Error on compile Nxlib

I modifed my Makefile, and the following is where I modifed:
MWIN=/home/nfs/microwindows/src
X11_INCLUDE=/usr/include
CC = gcc-3.3

And the following is the error infomation when I compiled Nxlib source.

*[nxlib-0.45]$ make*
gcc-3.3 -Wall -g -I/home/nfs/microwindows/src/include
-DX11_FONT_DIR1=\"/usr/lib/X11/fonts/100dpi\"
-DX11_FONT_DIR2=\"/usr/lib/X11/fonts/misc\"
-DX11_RGBTXT=\"/usr/lib/X11/rgb.txt\" -I. -fPIC -o Xrm.o -c Xrm.c
In file included from Xlcint.h:74,
                 from Xrm.c:55:
/usr/lib/gcc-lib/i486-linux-gnu/3.3.6/include/varargs.h:4:2: #error "GCC no
longer implements <varargs.h>."
/usr/lib/gcc-lib/i486-linux-gnu/3.3.6/include/varargs.h:5:2: #error "Revise
your code to use <stdarg.h>."
In file included from Xrm.c:55:
Xlcint.h:949: error: syntax error before "var"
Xlcint.h:954: error: syntax error before "var"
Xrm.c: In function `ReadInFile':
Xrm.c:1607: warning: implicit declaration of function `_XOpenFile'
make: *** [Xrm.o] Error 1

Can anyone tell me how to fix it.
-- 
----------------------------------------------

> -DX11_RGBTXT=\"/usr/lib/X11/rgb.txt\" -I. -fPIC -o Xrm.o -c Xrm.c
> In file included from Xlcint.h:74,
>                  from Xrm.c:55:
> /usr/lib/gcc-lib/i486-linux-gnu/3.3.6/include/varargs.h:4:2: #error "GCC
no
> longer implements <varargs.h>."
> /usr/lib/gcc-lib/i486-linux-gnu/3.3.6/include/varargs.h:5:2: #error
"Revise
> your code to use <stdarg.h>."
> In file included from Xrm.c:55:
> Xlcint.h:949: error: syntax error before "var"

The version of the X11 headers (and the included Xrm.c) are
not compatible with your version of the compiler's varargs.h library.

You can either update to a later version of Xrm.c from the X11
distribution (this was included solely to allow Xrm calls in NXLIB -
rarely needed), or just remove Xrm.o from the Makefile and
build an NXLIB without it.

Regards,

Greg