cyrus-sasl: only apply patch on FreeBSD to fix #12279

I noticed the breakage but forgot this patch in another branch.
https://github.com/NixOS/nixpkgs/pull/10816#issuecomment-168486249

pkgs/development/libraries/cyrus-sasl/default.nix

···
   };
 
   buildInputs =
-    [ openssl db gettext kerberos autoreconfHook ]
+    [ openssl db gettext kerberos ]
+    ++ lib.optional stdenv.isFreeBSD autoreconfHook
     ++ lib.optional stdenv.isLinux pam
     ++ lib.optional stdenv.isDarwin fixDarwinDylibNames;
 
   patches = [
     ./missing-size_t.patch # https://bugzilla.redhat.com/show_bug.cgi?id=906519
-    (
+  ] ++ lib.optional stdenv.isFreeBSD (
       fetchurl {
         url = "http://www.linuxfromscratch.org/patches/blfs/svn/cyrus-sasl-2.1.26-fixes-3.patch";
         sha256 = "1vh4pc2rxxm6yvykx0b7kg09jbcwcxwv5rs6yq2ag3y8p6a9x86w";
       }
-    )
-  ];
+    );
 
   configureFlags = [
     "--with-openssl=${openssl}"