Fix Lua examples for running under Lua 5.2

Includes cherry picking parts of
ce2760f77e

Examples/lua/embed/Makefile

@@ -4,6 +4,7 @@ TARGET     = embed
 SRCS       = example.c
 INTERFACE  = example.i
 LUA_INTERP = embed.c
+LIBS       = -lm
 
 # this is a little different to normal as we have our own special interpreter
 # which we want to static link
@@ -12,7 +13,7 @@ check: build
 
 build:
 	$(MAKE) -f $(TOP)/Makefile $(SWIGLIB) SRCS='$(SRCS)' SWIG='$(SWIG)' \
-	SWIGOPT='$(SWIGOPT)' TARGET='$(TARGET)' INTERFACE='example.i' LUA_INTERP='$(LUA_INTERP)' lua_static
+	SWIGOPT='$(SWIGOPT)' TARGET='$(TARGET)' LIBS='$(LIBS)' INTERFACE='example.i' LUA_INTERP='$(LUA_INTERP)' lua_static
 
 clean:
 	$(MAKE) -f $(TOP)/Makefile lua_clean

Examples/lua/embed/embed.c

@@ -18,6 +18,10 @@ We will be using the luaL_dostring()/lua_dostring() function to call into lua
 #include <lauxlib.h>
 #include <lualib.h>
 
+#if LUA_VERSION_NUM > 501
+#define lua_open luaL_newstate
+#endif
+
 /* the SWIG wrappered library */
 extern int luaopen_example(lua_State*L);