better(?) handling of '#define's for IEEE-related tricks + avoid using

IEEE trick for 64-bit integer types (lua_Integer on 64-bit machines)

llimits.h

@@ -1,5 +1,5 @@
 /*
-** $Id: llimits.h,v 1.96 2012/01/25 21:05:40 roberto Exp roberto $
+** $Id: llimits.h,v 1.97 2012/03/28 18:27:25 roberto Exp roberto $
 ** Limits, basic types, and some other `installation-dependent' definitions
 ** See Copyright Notice in lua.h
 */
@@ -209,31 +209,36 @@ typedef lu_int32 Instruction;
 
 #elif defined(LUA_IEEE754TRICK)		/* }{ */
 /* the next trick should work on any machine using IEEE754 with
-   a 32-bit integer type */
+   a 32-bit int type */
 
 union luai_Cast { double l_d; LUA_INT32 l_p[2]; };
 
 #if !defined(LUA_IEEEENDIAN)	/* { */
 #define LUAI_EXTRAIEEE	\
   static const union luai_Cast ieeeendian = {-(33.0 + 6755399441055744.0)};
-#define LUA_IEEEENDIAN		(ieeeendian.l_p[1] == 33)
+#define LUA_IEEEENDIANLOC	(ieeeendian.l_p[1] == 33)
 #else
+#define LUA_IEEEENDIANLOC	LUA_IEEEENDIAN
 #define LUAI_EXTRAIEEE		/* empty */
 #endif				/* } */
 
 #define lua_number2int32(i,n,t) \
   { LUAI_EXTRAIEEE \
     volatile union luai_Cast u; u.l_d = (n) + 6755399441055744.0; \
-    (i) = (t)u.l_p[LUA_IEEEENDIAN]; }
+    (i) = (t)u.l_p[LUA_IEEEENDIANLOC]; }
 
 #define luai_hashnum(i,n)  \
   { volatile union luai_Cast u; u.l_d = (n) + 1.0;  /* avoid -0 */ \
     (i) = u.l_p[0]; (i) += u.l_p[1]; }  /* add double bits for his hash */
 
 #define lua_number2int(i,n)		lua_number2int32(i, n, int)
-#define lua_number2integer(i,n)		lua_number2int32(i, n, lua_Integer)
 #define lua_number2unsigned(i,n)	lua_number2int32(i, n, lua_Unsigned)
 
+/* the trick can be expanded to lua_Integer when it is a 32-bit value */
+#if defined(LUA_IEEELL)
+#define lua_number2integer(i,n)		lua_number2int32(i, n, lua_Integer)
+#endif
+
 #endif				/* } */