Cannot Install Cairo Library

| Dear All,
| I am running Debian testing on my box and I have R 2.9.0 installed from 
| the standard repositories.
| I downloaded the package source from
| http://cran.r-project.org/web/packages/Cairo/index.html
| but when I try to install it on my system, this is what I get
| 
| $ sudo R CMD INSTALL Cairo_1.4-4.tar.gz
| * Installing to library ?/usr/local/lib/R/site-library?
| * Installing *source* package ?Cairo? ...
| checking for gcc... gcc -std=gnu99
[...]
| gcc -std=gnu99 -I/usr/share/R/include -D_REENTRANT -I/usr/include/cairo 
| -I/usr/include/pixman-1 -I/usr/include/freetype2 -I/usr/include/directfb 
| -I/usr/include/libpng12 -I. -Iinclude -g -O2 -fpic -g -O2 -c 
| xlib-backend.c -o xlib-backend.o
| xlib-backend.c:34:74: error: X11/Intrinsic.h: No such file or directory
                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

edd at ron:~$ dpkg -S `locate Intrinsic.h`
libxt-dev: /usr/include/X11/Intrinsic.h
edd at ron:~$

| xlib-backend.c: In function ?Rcairo_init_xlib?:
| xlib-backend.c:158: warning: implicit declaration of function 
| ?XrmUniqueQuark?
| make: *** [xlib-backend.o] Error 1
| ERROR: compilation failed for package ?Cairo?
| * Removing ?/usr/local/lib/R/site-library/Cairo?
| 
| Is there a header file missing? Or is there anything wrong with my system?
| Many thanks

Please run 'sudo apt-get install libxt-dev' and try again.

Dirk

Three out of two people have difficulties with fractions.