MINOR: lua: export applet and task handlers

The current functions are seen outside from the debugging code and are
convenient to export so that we can improve the thread dump output :

  void hlua_applet_tcp_fct(struct appctx *ctx);
  void hlua_applet_http_fct(struct appctx *ctx);
  struct task *hlua_process_task(struct task *task, void *context, unsigned short state);

Of course they are only available when USE_LUA is defined.

(cherry picked from commit 60409db0b1743d670e54244425f6e08c389b7dde)
[wt: backported to improve troubleshooting when the watchdog fires;
     while in 2.0 we also have hlua_applet_htx_fct(), it's not
     visible outside hlua_applet_http_fct() so we don't care]
Signed-off-by: Willy Tarreau <w@1wt.eu>
diff --git a/include/proto/hlua.h b/include/proto/hlua.h
index 7ad5a99..32468b7 100644
--- a/include/proto/hlua.h
+++ b/include/proto/hlua.h
@@ -27,6 +27,9 @@
 void hlua_ctx_destroy(struct hlua *lua);
 void hlua_init();
 int hlua_post_init();
+void hlua_applet_tcp_fct(struct appctx *ctx);
+void hlua_applet_http_fct(struct appctx *ctx);
+struct task *hlua_process_task(struct task *task, void *context, unsigned short state);
 
 #else /* USE_LUA */