Currently, in 1.x-stable while running Ruby 2.0.0 we have the following warnings when you compile the BSON C-extensions for the Ruby driver:
rake compile mkdir -p lib/bson_ext mkdir -p tmp/x86_64-darwin13.0.0/cbson/2.0.0 cd tmp/x86_64-darwin13.0.0/cbson/2.0.0 /Users/brandonblack/.rvm/rubies/ruby-2.0.0-p353/bin/ruby -I. ../../../../ext/cbson/extconf.rb checking for asprintf()... yes checking for ruby/st.h... yes checking for ruby/regex.h... yes checking for ruby/encoding.h... yes creating Makefile cd - cd tmp/x86_64-darwin13.0.0/cbson/2.0.0 make compiling ../../../../ext/cbson/bson_buffer.c compiling ../../../../ext/cbson/cbson.c ../../../../ext/cbson/cbson.c:849:31: warning: unused variable 'flags' [-Wunused-variable] int flags_length, flags = 0, i = 0; ^ ../../../../ext/cbson/cbson.c:849:42: warning: unused variable 'i' [-Wunused-variable] int flags_length, flags = 0, i = 0; ^ 2 warnings generated. compiling ../../../../ext/cbson/encoding_helpers.c linking shared-object bson_ext/cbson.bundle cd - mkdir -p tmp/x86_64-darwin13.0.0/stage/lib/bson_ext install -c tmp/x86_64-darwin13.0.0/cbson/2.0.0/cbson.bundle lib/bson_ext/cbson.bundle cp tmp/x86_64-darwin13.0.0/cbson/2.0.0/cbson.bundle tmp/x86_64-darwin13.0.0/stage/lib/bson_ext/cbson.bundle
We need to try and clean this up before release.