i'm noob.
This is my problem when i try.
Building native extensions. This could take a while…
ERROR: Error installing rails:
ERROR: Failed to build gem native extension.
current directory: /var/lib/gems/2.3.0/gems/nio4r-1.2.1/ext/nio4r
/usr/bin/ruby2.3 -r ./siteconf20160630-19108-12sbtb7.rb extconf.rb
mkmf.rb can't find header files for ruby at /usr/lib/ruby/include/ruby.h
extconf failed, exit code 1
Gem files will remain installed in /var/lib/gems/2.3.0/gems/nio4r-1.2.1 for inspection.
Results logged to /var/lib/gems/2.3.0/extensions/x86-linux/2.3.0/nio4r-1.2.1/gem_make.out
Best Answer
I needed to install ruby-dev:
Cf: This question on StackOverflow. It recommends
sudo apt-get install build-essential patch
first, but my system didn't need that.