Fetching: sparkr-0.4.1.gem (100%)
Successfully installed sparkr-0.4.1
Fetching: iStats-1.0.1.gem (100%)
Building native extensions. This could take a while...
ERROR: Error installing iStats:
ERROR: Failed to build gem native extension.
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/bin/ruby extconf.rb
mkmf.rb can't find header files for ruby at /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/include/ruby.h
Gem files will remain installed in /Library/Ruby/Gems/2.0.0/gems/iStats-1.0.1 for inspection.
Results logged to /Library/Ruby/Gems/2.0.0/gems/iStats-1.0.1/ext/osx_stats/gem_make.out
