diff --git a/pkgs/stdenv/generic/default.nix b/pkgs/stdenv/generic/default.nix
index fa9c18b2c374..4b988ef524a8 100644
--- a/pkgs/stdenv/generic/default.nix
+++ b/pkgs/stdenv/generic/default.nix
@@ -100,6 +100,10 @@ let
                || result.system == "i686-freebsd"
                || result.system == "i686-openbsd"
                || result.system == "i386-sunos";
+        isx86_64 = result.system == "x86_64-linux"
+               || result.system == "x86_64-darwin"
+               || result.system == "x86_64-freebsd"
+               || result.system == "x86_64-openbsd";
         is64bit = result.system == "x86_64-linux"
                 || result.system == "x86_64-darwin";