sudo gem install bson_ext -v '1.8.2'
Building native extensions. This could take a while...
ERROR: Error installing bson_ext:
ERROR: Failed to build gem native extension.

/usr/bin/ruby 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

make
compiling cbson.c
cbson.c: In function ‘write_element’:
cbson.c:316:17: warning: ignoring return value of ‘asprintf’, declared with attribute warn_unused_result [-Wunused-result]
compiling encoding_helpers.c
compiling bson_buffer.c
linking shared-object bson_ext/cbson.so

make install
/usr/bin/install -c -m 0755 cbson.so /usr/lib/ruby/gems/2.0.0/gems/bson_ext-1.8.2/ext/bson_ext/bson_ext
/usr/bin/install: cannot create regular file ‘/usr/lib/ruby/gems/2.0.0/gems/bson_ext-1.8.2/ext/bson_ext/bson_ext’: No such file or directory
make: *** [install-so] Error 1

Gem files will remain installed in /usr/lib/ruby/gems/2.0.0/gems/bson_ext-1.8.2 for inspection.
Results logged to /usr/lib/ruby/gems/2.0.0/gems/bson_ext-1.8.2/ext/cbson/gem_make.out