+ * Add an additional search directory for the protocol decoders.
+ *
+ * The specified directory is prepended (not appended!) to Python's sys.path,
+ * in order to search for sigrok protocol decoders in the specified
+ * directories first, and in the generic Python module directories (and in
+ * the current working directory) last. This avoids conflicts if there are
+ * Python modules which have the same name as a sigrok protocol decoder in
+ * sys.path or in the current working directory.