I tried installing a gem like I did before installing Yosemite, but now I\'m getting an error:
/Library/Ruby/Site/2.0.0/rubygems/ext/builder.rb:159:in `synchronize\': E
I had a same problem when I installed mysql via bitnami, Looks like you do not have all required mysql libraries .
I used brewsh and reinstalled mysql by
brew install mysql
sudo gem install mysql2
Also you need to load the dynamic library in your .profile file in the home directory, you can achieve this by adding these lines in .profile file .
export PATH=$PATH:$MYSQL
export DYLD_LIBRARY_PATH=/Applications/mysql/lib:$DYLD_LIBRARY_PATH
In the above two lines of code
/Applications/mysql/lib , is the path where your mysql libraries are installed , in yours it might be different please check and use as per your environment