diff --git a/neo/idlib/Parser.cpp b/neo/idlib/Parser.cpp
index b3cb7179f..33af7a847 100644
--- a/neo/idlib/Parser.cpp
+++ b/neo/idlib/Parser.cpp
@@ -625,7 +625,7 @@ void idParser::AddBuiltinDefines( void ) {
 	define_t *define;
 	struct builtin
 	{
-		char *string;
+		const char *string;
 		int id;
 	} builtin[] = {
 		{ "__LINE__",	BUILTIN_LINE },