We had this problem too.
Go to Window>Preferences>C/C++>Build>Settings
Under Settings, go to the Discovery tab. There will be an entry called "CDT GCC Built-in Compiler Settings". Click it. The box below (Language Settings Provider Options) will have a text box with text like "${COMMAND} ${FLAGS}..."
Append "arm-frc-linux-gnueabi-" to the beginning. Press "Ok".
Screenshot below:
