[perl-Glib] Glib::ParamSpec: mention that Gtk2::Builder doesn't support 'scalar' params

[Torsten Schönfeld <tsch src gnome org>]

commit da938fc624f91ac961c35a6c1de8af0a822764cb
Author: Kevin Ryde <user42 zip com au>
Date:   Sat Oct 30 15:23:21 2010 +0200

    Glib::ParamSpec: mention that Gtk2::Builder doesn't support 'scalar' params

 GParamSpec.xs |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)
---
diff --git a/GParamSpec.xs b/GParamSpec.xs
index 5a189a3..f543f4c 100644
--- a/GParamSpec.xs
+++ b/GParamSpec.xs
@@ -556,6 +556,12 @@ param_spec (class, name, nick, blurb, package, flags)
 =for apidoc
 ParamSpec to be used for any generic perl scalar, including references to
 complex objects.
+
+Currently C<Gtk2::Builder> cannot set object properties of this type
+(there's no hooks for property value parsing, as of Gtk 2.20), so
+prefer the builtin types if buildable support for an object matters.
+A C<boxed> of C<Glib::Strv> can give an array of strings.  A signal
+handler callback can do most of what a coderef might.
 =cut
 GParamSpec*
 scalar (class, name, nick, blurb, flags)