luaL_checkstack accepts NULL message.

Author: siffiejoe

c-api/compat-5.3.c

@@ -155,6 +155,18 @@ COMPAT53_API void luaL_checkversion (lua_State *L) {
 }
 
 
+COMPAT53_API void luaL_checkstack (lua_State *L, int sp, const char *msg) {
+  if (!lua_checkstack(L, sp+LUA_MINSTACK)) {
+    if (msg != NULL)
+      luaL_error(L, "stack overflow (%s)", msg);
+    else {
+      lua_pushliteral(L, "stack overflow");
+      lua_error(L);
+    }
+  }
+}
+
+
 COMPAT53_API int luaL_getsubtable (lua_State *L, int i, const char *name) {
   int abs_i = lua_absindex(L, i);
   luaL_checkstack(L, 3, "not enough stack slots");

c-api/compat-5.3.h

@@ -131,6 +131,9 @@ COMPAT53_API lua_Number lua_tonumberx (lua_State *L, int i, int *isnum);
 #define luaL_checkversion COMPAT53_CONCAT(COMPAT53_PREFIX, L_checkversion)
 COMPAT53_API void luaL_checkversion (lua_State *L);
 
+#define luaL_checkstack COMPAT53_CONCAT(COMPAT53_PREFIX, L_checkstack_53)
+COMPAT53_API void luaL_checkstack (lua_State *L, int sp, const char *msg);
+
 #define luaL_getsubtable COMPAT53_CONCAT(COMPAT53_PREFIX, L_getsubtable)
 COMPAT53_API int luaL_getsubtable (lua_State* L, int i, const char *name);