Bundle install: ERROR: Failed to build gem native extension. nio4r gem

bundle config build.nio4r --with-cflags="-std=c99"
bundle install

works for me

I solved it with:

sudo apt-get install libmysqlclient-dev
sudo apt-get install libpq-dev
sudo apt-get install libsqlite3-dev
sudo apt-get install libev-dev
rvm use 2.0.0
Reboot pc

If I run rails -v shows me:

• Rails 3.2.17

And now I can make Bundle install

I think the rails version was in conflict. I don't know why, maybe anyone can explain me.

If you are working on Mac OSX above version 10.11.x, the following approach worked for me:

gem install nio4r -v '1.1.0' -- with-cflags="-std=c99"