MINOR: lua: use bitfield and macro in place of integer and enum

In the future, the lua execution must return scheduling informations.
We want more than one flag, so I convert an integer used with an
enum into an interer used as bitfield.
diff --git a/include/proto/hlua.h b/include/proto/hlua.h
index b9530aa..1428673 100644
--- a/include/proto/hlua.h
+++ b/include/proto/hlua.h
@@ -7,6 +7,11 @@
 
 #include <types/hlua.h>
 
+/* The following macros are used to set flags. */
+#define HLUA_SET_RUN(__hlua)         do {(__hlua)->flags |= HLUA_RUN;} while(0)
+#define HLUA_CLR_RUN(__hlua)         do {(__hlua)->flags &= ~HLUA_RUN;} while(0)
+#define HLUA_IS_RUNNING(__hlua)      ((__hlua)->flags & HLUA_RUN)
+
 #define HLUA_INIT(__hlua) do { (__hlua)->T = 0; } while(0)
 
 /* Lua HAProxy integration functions. */
@@ -16,6 +21,8 @@
 
 #else /* USE_LUA */
 
+#define HLUA_IS_RUNNING(__hlua) 0
+
 #define HLUA_INIT(__hlua)
 
 /* Empty function for compilation without Lua. */