babl: fixed to build with introspection support

Note:

For building introspection support we need the real library and pkgconfig
files installed so we use 2 build loops, disabling introspection within
the first loop.

graphic/babl/babl.conf

@@ -0,0 +1,27 @@
+# --- SDE-COPYRIGHT-NOTE-BEGIN ---
+# This copyright note is auto-generated by ./scripts/Create-CopyPatch.
+#
+# Filename: package/.../babl/babl.conf
+# Copyright (C) 2011 The OpenSDE Project
+#
+# More information can be found in the files COPYING and README.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; version 2 of the License. A copy of the
+# GNU General Public License can be found in the file COPYING.
+# --- SDE-COPYRIGHT-NOTE-END ---
+
+# for building introspection support we need the real library and pkgconfig
+# files installed so we use 2 build loops, disabling introspection within
+# the first loop
+if pkginstalled gobject-introspection; then
+	buildloops=2
+fi
+
+babl_preconf() {
+	if [ "$buildloop" -eq 1 ]; then
+		var_append extraconfopt ' ' "--disable-introspection"
+	fi
+}
+hook_add preconf 5 'babl_preconf'