Error installing mysql2: Failed to build gem native extension
On Ubuntu/Debian and other distributions using aptitude:
sudo apt-get install libmysql-ruby libmysqlclient-devPackage libmysql-ruby has been phased out and replaced by ruby-mysql. This is where I found the solution.
If the above command doesn't work because libmysql-ruby cannot be found, the following should be sufficient:
sudo apt-get install libmysqlclient-devOn Red Hat/CentOS and other distributions using yum:
sudo yum install mysql-develOn Mac OS X with Homebrew:
brew install mysql
For MacOS Mojave:
gem install mysql2 -v '0.5.2' -- --with-ldflags=-L/usr/local/opt/openssl/lib --with-cppflags=-I/usr/local/opt/openssl/include