Rename hostDrv -> crossDrv, buildDrv -> nativeDrv

This is for consistency with terminology in stdenv (and the terms
"hostDrv" and "buildDrv" are not very intuitive, even if they're
consistent with GNU terminology).

pkgs/development/libraries/SDL/default.nix

@@ -43,7 +43,7 @@ stdenv.mkDerivation rec {
   configureFlags = configureFlagsFun { inherit alsaLib; };
 
   crossAttrs = {
-      configureFlags = configureFlagsFun { alsaLib = alsaLib.hostDrv; };
+      configureFlags = configureFlagsFun { alsaLib = alsaLib.crossDrv; };
   };
 
   passthru = {inherit openglSupport;};