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/src/hlua.c b/src/hlua.c
index d2708f8..813aa72 100644
--- a/src/hlua.c
+++ b/src/hlua.c
@@ -6237,7 +6237,7 @@
  * Task wrapper are longjmp safe because the only one Lua code
  * executed is the safe hlua_ctx_resume();
  */
-static struct task *hlua_process_task(struct task *task, void *context, unsigned short state)
+struct task *hlua_process_task(struct task *task, void *context, unsigned short state)
 {
 	struct hlua *hlua = context;
 	enum hlua_exec status;
@@ -7045,7 +7045,7 @@
 	return 1;
 }
 
-static void hlua_applet_tcp_fct(struct appctx *ctx)
+void hlua_applet_tcp_fct(struct appctx *ctx)
 {
 	struct stream_interface *si = ctx->owner;
 	struct stream *strm = si_strm(si);
@@ -7417,7 +7417,7 @@
 	goto done;
 }
 
-static void hlua_applet_http_fct(struct appctx *ctx)
+void hlua_applet_http_fct(struct appctx *ctx)
 {
 	struct stream_interface *si = ctx->owner;
 	struct stream *strm = si_strm(si);