rsvg-cairo.h:33:10: fatal error: 'cairo.h' file not found

[AN]

Trying to install Gnome2 in a Vbox virtual machine fails with:

cc: warning: unknown warning option '-Wunsafe-loop-optimizations'; did you 
mean '-Wout-of-line-declaration'?
warning: unknown warning option '-Wunsafe-loop-optimizations'; did you 
mean '-Wout-of-line-declaration'? [-Wunknown-warning-option]
rsvg-convert.c:248:9: warning: 'rsvg_handle_set_size_callback' is 
deprecated [-Wdeprecated-declarations]
         rsvg_handle_set_size_callback (rsvg, rsvg_cairo_size_callback, 
&dimensions, NULL);
         ^
./rsvg.h:201:6: note: 'rsvg_handle_set_size_callback' declared here
void rsvg_handle_set_size_callback (RsvgHandle * handle,
      ^
2 warnings generated.
   CC     rsvg_convert-rsvg-size-callback.o
cc: warning: unknown warning option '-Wunsafe-loop-optimizations'; did you 
mean '-Wout-of-line-declaration'?
warning: unknown warning option '-Wunsafe-loop-optimizations'; did you 
mean '-Wout-of-line-declaration'? [-Wunknown-warning-option]
1 warning generated.
   CCLD   rsvg-convert
cc: warning: unknown warning option '-Wunsafe-loop-optimizations'; did you 
mean '-Wout-of-line-declaration'?
   GISCAN Rsvg-2.0.gir
In file included from <stdin>:4:
In file included from 
/usr/ports/graphics/librsvg2/work/librsvg-2.36.4/rsvg.h:239:
./rsvg-cairo.h:33:10: fatal error: 'cairo.h' file not found
#include <cairo.h>
          ^
1 error generated.
Error while processing the source.
gmake[2]: *** [Rsvg-2.0.gir] Error 1
gmake[2]: Leaving directory 
`/usr/ports/graphics/librsvg2/work/librsvg-2.36.4'
gmake[1]: *** [all-recursive] Error 1
gmake[1]: Leaving directory 
`/usr/ports/graphics/librsvg2/work/librsvg-2.36.4'
gmake: *** [all] Error 2
*** [do-build] Error code 1

Stop in /usr/ports/graphics/librsvg2.
*** [lib-depends] Error code 1

Stop in /usr/ports/x11/gnome-panel.
*** [install] Error code 1

Stop in /usr/ports/x11/gnome-panel.
*** [lib-depends] Error code 1

Stop in /usr/ports/x11/gnome-applets.
*** [install] Error code 1

Stop in /usr/ports/x11/gnome-applets.
*** [run-depends] Error code 1

Stop in /usr/ports/x11/gnome2.
*** [install] Error code 1

Stop in /usr/ports/x11/gnome2.



FreeBSD FBSD-10 10.0-CURRENT FreeBSD 10.0-CURRENT #0 r247825: Mon Mar  4 
20:13:02 CST 2013     root at FBSD-10:/usr/obj/usr/src/sys/GENERIC  amd64

Ports tree is up to date.  Any help is appreciated, thanks in advance.