Build separate gem for JRuby

Author: kanwei

algorithms.gemspec

@@ -2,15 +2,17 @@
 
 Gem::Specification.new do |s|
   s.name = "algorithms"
-  s.version = "0.6.0"
+  s.version = "0.6.1"
 
   s.authors = ["Kanwei Li"]
   s.email = "[email protected]"
   s.license = 'MIT'
   s.date = "2013-01-22"
   s.summary = "Useful algorithms and data structures for Ruby. Optional C extensions."
   s.description = "Heap, Priority Queue, Deque, Stack, Queue, Red-Black Trees, Splay Trees, sorting algorithms, and more"
-  unless defined?(RUBY_ENGINE) && RUBY_ENGINE == 'jruby'
+  if defined?(RUBY_ENGINE) && RUBY_ENGINE == 'jruby'
+    s.platform = "java"
+  else
     s.extensions = ["ext/algorithms/string/extconf.rb", "ext/containers/bst/extconf.rb", "ext/containers/deque/extconf.rb", "ext/containers/rbtree_map/extconf.rb", "ext/containers/splaytree_map/extconf.rb"]
   end
   s.files = ["Gemfile", "CHANGELOG.markdown", "Manifest", "README.markdown", "Rakefile", "algorithms.gemspec", "benchmarks/deque.rb", "benchmarks/sorts.rb", "benchmarks/treemaps.rb", "ext/algorithms/string/extconf.rb", "ext/algorithms/string/string.c", "ext/containers/bst/bst.c", "ext/containers/bst/extconf.rb", "ext/containers/deque/deque.c", "ext/containers/deque/extconf.rb", "ext/containers/rbtree_map/extconf.rb", "ext/containers/rbtree_map/rbtree.c", "ext/containers/splaytree_map/extconf.rb", "ext/containers/splaytree_map/splaytree.c", "lib/algorithms.rb", "lib/algorithms/search.rb", "lib/algorithms/sort.rb", "lib/algorithms/string.rb", "lib/containers/deque.rb", "lib/containers/heap.rb", "lib/containers/kd_tree.rb", "lib/containers/priority_queue.rb", "lib/containers/queue.rb", "lib/containers/rb_tree_map.rb", "lib/containers/splay_tree_map.rb", "lib/containers/stack.rb", "lib/containers/suffix_array.rb", "lib/containers/trie.rb", "spec/bst_gc_mark_spec.rb", "spec/bst_spec.rb", "spec/deque_gc_mark_spec.rb", "spec/deque_spec.rb", "spec/heap_spec.rb", "spec/kd_expected_out.txt", "spec/kd_test_in.txt", "spec/kd_tree_spec.rb", "spec/map_gc_mark_spec.rb", "spec/priority_queue_spec.rb", "spec/queue_spec.rb", "spec/rb_tree_map_spec.rb", "spec/search_spec.rb", "spec/sort_spec.rb", "spec/splay_tree_map_spec.rb", "spec/stack_spec.rb", "spec/string_spec.rb", "spec/suffix_array_spec.rb", "spec/trie_spec.rb"]