I have an error compiling xfcalendar-4.2.1 on my gentoo.
I report here because I think the problem is really in xfcalendar-4.2.1 as I
tried to compile the tar.gz with configure, make

The problem only shows up with --enable-debug=full

Reproducible: Always
Steps to Reproduce:
1../configure --enable-debug=full
2.make
3. 

Actual Results:  
if gcc -DHAVE_CONFIG_H -I. -I. -I..    -DXTHREADS -D_REENTRANT -DXUSE_MTSAFE_API
-I/usr/include/xfce4 -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 -I/usr/include/xfce4
-I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include
-DPACKAGE_DATA_DIR=\""/usr/local/share"\"
-DPACKAGE_LOCALE_DIR=\""/usr/local/share/locale"\" -g -O2 -g3 -Wall -Werror
-DXFCE_DISABLE_DEPRECATED -MT xfcalendar-callbacks.o -MD -MP -MF
".deps/xfcalendar-callbacks.Tpo" -c -o xfcalendar-callbacks.o `test -f
'callbacks.c' || echo './'`callbacks.c; \
then mv -f ".deps/xfcalendar-callbacks.Tpo" ".deps/xfcalendar-callbacks.Po";
else rm -f ".deps/xfcalendar-callbacks.Tpo"; exit 1; fi
callbacks.c: In function `manageAppointment':
callbacks.c:182: error: `ctl_start' undeclared (first use in this function)
callbacks.c:182: error: (Each undeclared identifier is reported only once
callbacks.c:182: error: for each function it appears in.)
callbacks.c:182: error: `ctl_end' undeclared (first use in this function)
callbacks.c:183: error: `ctl_text' undeclared (first use in this function)
callbacks.c: In function `on_btClose_clicked':
callbacks.c:213: warning: implicit declaration of function `dialogWin'
make[2]: *** [xfcalendar-callbacks.o] Error 1
make[2]: Leaving directory
`/var/tmp/portage/xfcalendar-4.2.1/work/xfcalendar-4.2.1/src'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/var/tmp/portage/xfcalendar-4.2.1/work/xfcalendar-4.2.1'
make: *** [all] Error 2


Expected Results:  
Compiled