diff --git a/pkgs/stdenv/generic/default.nix b/pkgs/stdenv/generic/default.nix
index 1d7aaae7ccd..fa2dc516ff6 100644
--- a/pkgs/stdenv/generic/default.nix
+++ b/pkgs/stdenv/generic/default.nix
@@ -97,6 +97,14 @@ let
                || result.system == "armv5tel-linux";
         isSunOS = result.system == "i386-sunos";
         isCygwin = result.system == "i686-cygwin";
+	isFreeBSD = result.system == "i686-freebsd"
+	       || result.system == "x86_64-freebsd";
+	isOpenBSD = result.system == "i686-openbsd"
+	       || result.system == "x86_64-openbsd";
+	isBSD = result.system == "i686-freebsd"
+	       || result.system == "x86_64-freebsd"
+	       || result.system == "i686-openbsd"
+	       || result.system == "x86_64-openbsd";
         isi686 = result.system == "i686-linux"
                || result.system == "i686-darwin"
                || result.system == "i686-freebsd"