Add $(use_enable introspection) to G2CONF to ensure that the introspection
USE flag has an actual effect.

--- a/gdl-3.0.2.ebuild
+++ b/gdl-3.0.2.ebuild
@@ -27,4 +26,8 @@
 	>=dev-util/intltool-0.40.1
 	doc? ( >=dev-util/gtk-doc-1.4 )"
 
-DOCS="AUTHORS ChangeLog MAINTAINERS NEWS README"
+pkg_setup() {
+	G2CONF="${G2CONF}
+		$(use_enable introspection)"
+	DOCS="AUTHORS ChangeLog MAINTAINERS NEWS README"
+}