diff --git a/contrib/flex/src/flex.skl b/contrib/flex/src/flex.skl
index 242645f53245..c23b944ea473 100644
--- a/contrib/flex/src/flex.skl
+++ b/contrib/flex/src/flex.skl
@@ -1863,7 +1863,11 @@ m4_ifdef( [[M4_YY_USE_LINENO]],
 				case EOB_ACT_END_OF_FILE:
 					{
 					if ( yywrap( M4_YY_CALL_ONLY_ARG ) )
+#ifdef YY_FLEX_LEX_COMPAT
 						return 0;
+#else
+						return EOF;
+#endif
 
 					if ( ! YY_G(yy_did_buffer_switch_on_eof) )
 						YY_NEW_FILE;