diff --git a/mlton.spec b/mlton.spec
index b31f7be..bb5de67 100644
--- a/mlton.spec
+++ b/mlton.spec
@@ -29,7 +29,7 @@ BuildRequires:	mlton
 
 Requires:	gmp-devel gcc
 
-# not yet available for 64-bit arch
+# not yet available for 64-bit arch (#198764)
 ExcludeArch:	x86_64