This is a more generic solution; while the sanitizer support can be used
only for sanitizer instrumented builds, the multilib support can be used
to build other variants such as noexcept which is what we would like to use
The name CMake target name uses the target name, same as for the regular
runtimes build and the name of the multilib, concatenated with '+'. The
libraries are installed in a subdirectory named after the multilib.