[devhelp] libdevhelp: Add back empty dh_init() implementation to not break ABI

[Frederic Peters <fpeters src gnome org>]

commit 2c6123ce370f88d13f3c44f0a40c1c939dfe456a
Author: Carl-Anton Ingmarsson <ca ingmarsson gmail com>
Date:   Mon Jan 21 23:49:44 2013 +0100

    libdevhelp: Add back empty dh_init() implementation to not break ABI
    
    https://bugzilla.gnome.org/show_bug.cgi?id=692242

 src/Makefile.am |    1 +
 src/dh-common.c |   27 +++++++++++++++++++++++++++
 2 files changed, 28 insertions(+), 0 deletions(-)
---
diff --git a/src/Makefile.am b/src/Makefile.am
index 0776177..4b70e5d 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -76,6 +76,7 @@ libdevhelp_3_la_SOURCES =				\
 	dh-assistant.c					\
 	dh-assistant-view.c				\
 	dh-book-manager.c				\
+	dh-common.c						\
 	dh-language.c					\
 	dh-book.c					\
 	dh-book-tree.c					\
diff --git a/src/dh-common.c b/src/dh-common.c
new file mode 100644
index 0000000..cdf41a8
--- /dev/null
+++ b/src/dh-common.c
@@ -0,0 +1,27 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 8 -*- */
+/*
+ * Copyright (C) 2012 Aleksander Morgado <aleksander gnu org>
+ *
+ * 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; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#include "config.h"
+#include "devhelp.h"
+
+void
+dh_init (void)
+{
+}