Added libgd as a submodule, until GTK+ 3.10 comes out

libgd provides some neat widgets, like a header similar to
GTK+ 3.10's GtkHeaderBar, which comes in handy when generating the
window headers.

autogen.sh

@@ -5,6 +5,7 @@ srcdir=`dirname $0`
 test -z "$srcdir" && srcdir=.
 
 PKG_NAME="astrognome"
+ACLOCAL_FLAGS="-I libgd $ACLOCAL_FLAGS"
 
 (test -f $srcdir/configure.ac \
   && test -f $srcdir/src/astrognome.c) || {