diff --git a/pkgs/development/tools/parsing/ragel/default.nix b/pkgs/development/tools/parsing/ragel/default.nix
index 594ec7de53a2..753c91aa6880 100644
--- a/pkgs/development/tools/parsing/ragel/default.nix
+++ b/pkgs/development/tools/parsing/ragel/default.nix
@@ -24,6 +24,7 @@ stdenv.mkDerivation rec {
     homepage = http://www.complang.org/ragel;
     description = "State machine compiler";
     license = licenses.gpl2;
+    platforms = platforms.unix;
     maintainers = with maintainers; [ pSub ];
   };
 }