Added (gcc,g++)-multilib deps for Fedora

This will only work for x86 machines because Fedora doesn't currently
have a package which installs these libraries for the *other*
sub-architectures that are available on the current arch. A better
solution should be found.
Merge pull request #3656 from cottsay/gcc-multilib-fix

Add (gcc,g++)-multilib deps for Fedora