[glib] Document libffi as new dependency

[Matthias Clasen <matthiasc src gnome org>]

commit 9bcf89cd70946be7c724cbeac9cd1c028f74ea6e
Author: Matthias Clasen <mclasen redhat com>
Date:   Mon Aug 8 23:16:07 2011 +0200

    Document libffi as new dependency

 INSTALL.in        |    1 +
 README.in         |    8 ++++++++
 gobject/gsignal.c |    2 +-
 3 files changed, 10 insertions(+), 1 deletions(-)
---
diff --git a/INSTALL.in b/INSTALL.in
index 617eb92..d8134ff 100644
--- a/INSTALL.in
+++ b/INSTALL.in
@@ -68,6 +68,7 @@ Some of the mimetype-related functionality in GIO requires the
 update-mime-database and update-desktop-database utilities, which
 are part of shared-mime-info and desktop-file-utils, respectively.
 
+GObject uses libffi to implement generic marshalling functionality.
 
 The Nitty-Gritty
 ================
diff --git a/README.in b/README.in
index c0f6a8a..6ac99d8 100644
--- a/README.in
+++ b/README.in
@@ -24,6 +24,14 @@ Installation
 
 See the file 'INSTALL'
 
+Notes about GLib 2.30
+=====================
+
+* GObject includes a generic marshaller, g_cclosure_marshal_generic.
+  To use it, simply specify NULL as the marshaller in g_signal_new().
+  The generic marshaller is implemented with libffi, and consequently
+  GObject depends on libffi now.
+
 Notes about GLib 2.28
 =====================
 
diff --git a/gobject/gsignal.c b/gobject/gsignal.c
index 59b9c9e..4d96087 100644
--- a/gobject/gsignal.c
+++ b/gobject/gsignal.c
@@ -1310,7 +1310,7 @@ g_signal_query (guint         signal_id,
  * <code>super_class->signal_handler = my_signal_handler</code>. Instead they
  * will have to use g_signal_override_class_handler().
  *
- * If c_marshaller is %NULL @g_cclosure_marshal_generic will be used as
+ * If c_marshaller is %NULL, g_cclosure_marshal_generic() will be used as
  * the marshaller for this signal.
  *
  * Returns: the signal id