Unable to compile all panel plugins

[Harold Aling]

I'm using xfce from SVN and after rebuilding my entire system (gentoo) I 
can't seem to compile any panel plugin.

This example is from the xfce4-clipman-0.4.1-r1 ebuild:

mkdir .libs
i686-pc-linux-gnu-gcc -DHAVE_CONFIG_H -I. -I. -I.. -DXTHREADS 
-D_REENTRANT -DXUSE_MTSAFE_API -I/usr/include/xfce4 
-I/usr/include/libxml2 -I/usr/include/gtk-2.0 -I/usr/lib/gtk-2.0/include 
-I/usr/include/pango-1.0 -I/usr/include/freetype2 
-I/usr/include/freetype2/config -I/usr/include/glib-2.0 
-I/usr/lib/glib-2.0/include -I/usr/include/atk-1.0 
-DXFCE_PANEL_THREADED=1 "-DXFCE_PANEL_LOCK()=gdk_threads_enter()" 
"-DXFCE_PANEL_UNLOCK()=gdk_threads_leave()" -O3 -mcpu=prescott 
-march=prescott -fomit-frame-pointer -pipe -MT libclipman_la-clipman.lo 
-MD -MP -MF .deps/libclipman_la-clipman.Tpo -c clipman.c  -fPIC -DPIC -o 
.libs/libclipman_la-clipman.o
In file included from clipman.c:33:
/usr/include/xfce4/libxfce4util/i18n.h:24:2: #error "Only 
<libxfce4util/libxfce4util.h> can be included directly, this file may 
disappear or change contents"
make[2]: *** [libclipman_la-clipman.lo] Error 1
make[2]: Leaving directory 
`/var/tmp/portage/xfce4-clipman-0.4.1-r1/work/xfce4-clipman-plugin-0.4.1/panel-plugin' 

make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory 
`/var/tmp/portage/xfce4-clipman-0.4.1-r1/work/xfce4-clipman-plugin-0.4.1'
make: *** [all] Error 2

Ideas?