Fix src_prepare phase

Package-Manager: portage-2.2.27

app-emulation/libvirt-glib/libvirt-glib-0.2.3.ebuild

@@ -43,6 +43,11 @@ pkg_setup() {
 	use python && python-single-r1_pkg_setup
 }
 
+src_prepare() {
+	gnome2_src_prepare
+	use vala && vala_src_prepare
+}
+
 src_configure() {
 	gnome2_src_configure \
 		--disable-test-coverage \