Compiling into /usr/lib64 instead of /usr/lib

Is there an easy way to switch the install directory from /usr/lib to
/usr/lib64. Some multilib systems like Fedora x86_64 require libraries to
be placed in /usr/lib64 if they are 64-bit.

Simply moving the files to lib64 breaks the install (not surprising). I
glanced through some of the CMake files in Swift and /usr/lib looks to be
hard-coded in a number of places.