add Lua and basic Lua->C/C++ integration test, in preparation for Bullet demos setup using Lua scripts.

btgui/lua-5.2.3/src/lapi.h

@@ -0,0 +1,24 @@
+/*
+** $Id: lapi.h,v 2.7.1.1 2013/04/12 18:48:47 roberto Exp $
+** Auxiliary functions from Lua API
+** See Copyright Notice in lua.h
+*/
+
+#ifndef lapi_h
+#define lapi_h
+
+
+#include "llimits.h"
+#include "lstate.h"
+
+#define api_incr_top(L)   {L->top++; api_check(L, L->top <= L->ci->top, \
+				"stack overflow");}
+
+#define adjustresults(L,nres) \
+    { if ((nres) == LUA_MULTRET && L->ci->top < L->top) L->ci->top = L->top; }
+
+#define api_checknelems(L,n)	api_check(L, (n) < (L->top - L->ci->func), \
+				  "not enough elements in the stack")
+
+
+#endif