- added core lump checks for ZScript.

- load internal shaders only from file 0. This does not contain aborts, like most of the other checks,but it will now refuse to load any core shader file from anything but gzdoom.pk3.

src/scripting/zscript/zcc_parser.cpp

@@ -316,6 +316,8 @@ static void DoParse(int lumpnum)
 	FScanner sc;
 	void *parser;
 	ZCCToken value;
+	auto baselump = lumpnum;
+	auto fileno = Wads.GetLumpFile(lumpnum);
 
 	parser = ZCCParseAlloc(malloc);
 	ZCCParseState state;
@@ -344,6 +346,13 @@ static void DoParse(int lumpnum)
 		}
 		else
 		{
+			auto fileno2 = Wads.GetLumpFile(lumpnum);
+			if (fileno == 0 && fileno2 != 0)
+			{
+				I_FatalError("File %s is overriding core lump %s.",
+					Wads.GetWadFullName(Wads.GetLumpFile(baselump)), Includes[i].GetChars());
+			}
+
 			ParseSingleFile(nullptr, lumpnum, parser, state);
 		}
 	}