Cross compilers, but not libraries?

[Tom Horsley]

In fedora 23, there are cross compilers available in the repos.
For example:

gcc-aarch64-linux-gnu.i686 : Cross-build binary utilities for aarch64-linux-gnu
gcc-c++-aarch64-linux-gnu.i686 : Cross-build binary utilities for
                               : aarch64-linux-gnu
binutils-aarch64-linux-gnu.i686 : Cross-build binary utilities for
                                : aarch64-linux-gnu

But, there are no cross libraries apparently. Is there some
standard way people get libraries for cross development?