boost: use correct platform

"platforms.all" could include any possible os (even a machine with no
OS at all!). We can’t possible hope to support all of that, so need to
be more specific.

pkgs/development/libraries/boost/generic.nix

@@ -109,7 +109,7 @@ stdenv.mkDerivation {
     description = "Collection of C++ libraries";
     license = stdenv.lib.licenses.boost;
 
-    platforms = (if versionOlder version "1.59" then remove "aarch64-linux" else id) platforms.all;
+    platforms = (if versionOlder version "1.59" then remove "aarch64-linux" else id) (platforms.unix ++ platforms.windows);
     maintainers = with maintainers; [ peti wkennington ];
   };