clucene-core: expand platforms to unix

pkgs/development/libraries/clucene-core/default.nix

···
       CLucene is a port of the very popular Java Lucene text search engine API.
     '';
     homepage = "http://clucene.sourceforge.net";
-    platforms = platforms.linux;
+    platforms = platforms.unix;
     license = with licenses; [ asl20 lgpl2 ];
   };
 }