use c++ for some more sources

Do a (superficial) port to c++ of some of the c sources. Update
deps. Fix a few compiler warnings.

lib/mu-bookmarks.hh

@@ -0,0 +1,81 @@
+/*
+** Copyright (C) 2008-2020 Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
+**
+** 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 3, 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+**
+*/
+
+#ifndef MU_BOOKMARKS_HH__
+#define MU_BOOKMARKS_HH__
+
+#include <glib.h>
+/**
+ * @addtogroup MuBookmarks
+ * Functions for dealing with bookmarks
+ * @{
+ */
+
+/*! \struct MuBookmarks
+ * \brief Opaque structure representing a sequence of bookmarks
+ */
+struct MuBookmarks;
+
+
+/**
+ * create a new bookmarks object. when it's no longer needed, use
+ * mu_bookmarks_destroy
+ *
+ * @param bmpath path to the bookmarks file
+ *
+ * @return a new BookMarks object, or NULL in case of error
+ */
+MuBookmarks *mu_bookmarks_new (const gchar *bmpath)
+    G_GNUC_MALLOC G_GNUC_WARN_UNUSED_RESULT;
+
+/**
+ * destroy a bookmarks object
+ *
+ * @param bm a bookmarks object, or NULL
+ */
+void         mu_bookmarks_destroy (MuBookmarks *bm);
+
+
+/**
+ * get the value for some bookmark
+ *
+ * @param bm a valid bookmarks object
+ * @param name name of the bookmark to retrieve
+ *
+ * @return the value of the bookmark or NULL in case in error, e.g. if
+ * the bookmark was not found
+ */
+const gchar* mu_bookmarks_lookup (MuBookmarks *bm, const gchar *name);
+
+typedef void (*MuBookmarksForeachFunc) (const gchar *key, const gchar *val,
+					gpointer user_data);
+
+/**
+ * call a function for each bookmark
+ *
+ * @param bm a valid bookmarks object
+ * @param func a callback function to be called for each bookmarks
+ * @param user_data a user pointer passed to the callback
+ */
+void         mu_bookmarks_foreach (MuBookmarks *bm, MuBookmarksForeachFunc func,
+				   gpointer user_data);
+
+/** @} */
+
+#endif /*__MU_BOOKMARKS_H__*/