Stick to the Lua 5.2 C API

Aegisub requires Luajit implementing Lua 5.2, but the code was making a
mixture of Lua 5.1 and Lua 5.2 C API calls which happened to work
because luajit's standards compliance is loose.

Tested with some out of tree patches to make Aegisub work on an
unsupported platform (OpenBSD, official Lua).

libaegisub/lua/modules/lpeg.c

@@ -39,10 +39,6 @@
 #undef lua_objlen
 #define lua_objlen	lua_rawlen
 
-#undef luaL_register
-#define luaL_register(L,n,f) \
-	{ if ((n) == NULL) luaL_setfuncs(L,f,0); else luaL_newlib(L,f); }
-
 #endif
 
 
@@ -2379,8 +2375,8 @@ int luaopen_lpeg (lua_State *L) {
   luaL_newmetatable(L, PATTERN_T);
   lua_pushnumber(L, MAXBACK);
   lua_setfield(L, LUA_REGISTRYINDEX, MAXSTACKIDX);
-  luaL_register(L, NULL, metapattreg);
-  luaL_register(L, "lpeg", pattreg);
+  luaL_setfuncs(L, metapattreg, 0);
+  luaL_newlib(L, pattreg);
   lua_pushliteral(L, "__index");
   lua_pushvalue(L, -2);
   lua_settable(L, -4);

src/auto4_lua.cpp

@@ -466,7 +466,6 @@ namespace {
 		stackcheck.check_stack(0);
 
 		// make "aegisub" table
-		lua_pushstring(L, "aegisub");
 		lua_createtable(L, 0, 13);
 
 		set_field<LuaCommand::LuaRegister>(L, "register_macro");
@@ -487,7 +486,7 @@ namespace {
 		set_field<lua_set_status_text>(L, "set_status_text");
 
 		// store aegisub table to globals
-		lua_settable(L, LUA_GLOBALSINDEX);
+		lua_setglobal(L, "aegisub");
 		stackcheck.check_stack(0);
 
 		// load user script

src/auto4_lua_assfile.cpp

@@ -72,15 +72,15 @@ namespace {
 	std::string get_string_field(lua_State *L, const char *name, const char *line_class)
 	{
 		get_field(L, name, line_class, lua_isstring);
-		std::string ret(lua_tostring(L, -1), lua_strlen(L, -1));
+		std::string ret = lua_tostring(L, -1);
 		lua_pop(L, 1);
 		return ret;
 	}
 
 	agi::Color get_color_field(lua_State *L, const char *name, const char *line_class)
 	{
 		get_field(L, name, line_class, lua_isstring);
-		agi::Color ret(std::string_view(lua_tostring(L, -1), lua_strlen(L, -1)));
+		agi::Color ret = std::string_view(lua_tostring(L, -1));
 		lua_pop(L, 1);
 		return ret;
 	}

subprojects/luabins/src/luabins.c

@@ -82,7 +82,10 @@ LUALIB_API int luaopen_luabins(lua_State * L)
   /*
   * Register module
   */
-  luaL_register(L, "luabins", R);
+  lua_newtable(L);
+  luaL_setfuncs(L, R, 0);
+  lua_pushvalue(L, -1);
+  lua_setglobal(L, "mylib");
 
   /*
   * Register module information

subprojects/luabins/src/save.c

@@ -88,7 +88,7 @@ static int save_table(
       TODO: Note inelegant downsize from size_t to int.
             Handle integer overflow here.
     */
-    int array_size = luabins_min(total_size, (int)lua_objlen(L, index));
+    int array_size = luabins_min(total_size, (int)lua_rawlen(L, index));
     int hash_size = luabins_max(0, total_size - array_size);
 
     result = lbs_writeTableHeaderAt(sb, header_pos, array_size, hash_size);