GNUInstallDirs should not use /usr/lib64 for Alpine Linux
When setting CMAKE_INSTALL_PREFIX to /usr, CMAKE_INSTALL_FULL_LIBDIR is set to /usr/lib64, which is not correct for Alpine Linux.
This is similar to #15373 (closed)
We used a downstream patch for Alpine, but apparently it broke other things so it would be better to have this fixed in upstream cmake.