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.