* add mu_util_guess_mu_homedir and mu_util_guess_xapian_dir and use them

src/mu-util.h

@@ -51,6 +51,30 @@ char*       mu_util_dir_expand (const char* path) G_GNUC_WARN_UNUSED_RESULT;
 char*       mu_util_guess_maildir (void) G_GNUC_WARN_UNUSED_RESULT;
 
 
+/**
+ * guess the place of the mu homedir (typically, ~/.mu). Note, this
+ * directory does not necessarily exist. mu_util_check_dir can be use
+ * to check that
+ *  
+ * @return the guessed mu homedir, which needs to be freed with g_free
+ * when no longer needed.
+ */
+gchar* mu_util_guess_mu_homedir (void);
+
+
+/**
+ * guess the place of the xapian database (typically,
+ * ~/.mu/xapian/). Note, this directory does not necessarily
+ * exist. mu_util_check_dir can be use to check that
+ *
+ * @param muhome the mu home directory or NULL, in which the muhome
+ * directoy will be guessed as well
+ *  
+ * @return the guessed xapian dir, which needs to be freed with g_free
+ * when no longer needed.
+ */
+gchar* mu_util_guess_xapian_dir (const gchar *muhome);
+
 
 /**
  * if path exists, check that's a read/writeable dir; otherwise try to