OS X Unable to build mysql2 gem

The problem:

linking shared-object mysql2/mysql2.bundle
ld: library not found for -lssl

The solution:

gem install mysql2 -- --with-cflags=\"-I/usr/local/opt/openssl/include\" --with-ldflags=\"-L/usr/local/opt/openssl/lib\"

Note that these are mainly notes to myself, but if you find them helpful then you're welcome.