Fix some compiler warnings

`-Weverything' seems to have found a few problems.

Also enabled clang sanitizers by default.

src/zyklonb.c

@@ -55,8 +55,8 @@ struct plugin_data
 	LIST_HEADER (plugin_data)
 	struct bot_context *ctx;            ///< Parent context
 
-	pid_t pid;                          ///< PID of the plugin process
 	char *name;                         ///< Plugin identifier
+	pid_t pid;                          ///< PID of the plugin process
 
 	bool is_zombie;                     ///< Whether the child is a zombie
 	bool initialized;                   ///< Ready to exchange IRC messages
@@ -66,9 +66,9 @@ struct plugin_data
 	// we don't stall on plugins unnecessarily.
 
 	int read_fd;                        ///< The read end of the comm. pipe
-	struct str read_buffer;             ///< Unprocessed input
-
 	int write_fd;                       ///< The write end of the comm. pipe
+
+	struct str read_buffer;             ///< Unprocessed input
 	struct str write_buffer;            ///< Output yet to be sent out
 };
 
@@ -1610,7 +1610,7 @@ on_signal_pipe_readable (const struct pollfd *fd, struct bot_context *ctx)
 		//       "plugin `name' died like a dirty jewish pig"; use `status'
 		if (!plugin->is_zombie && WIFSIGNALED (status))
 		{
-			char *notes = "";
+			const char *notes = "";
 #ifdef WCOREDUMP
 			if (WCOREDUMP (status))
 				notes = " (core dumped)";