Starting with MacOSX 10.11 ("El Capitan") non-system programs must not be installed in "/usr/bin", "/usr/lib", etc. The operating system does not allow installing anything there without running in a system process and signed for system use (only Apple can do that).
Instead one needs to install into the "/usr/local"node as root which itself my have a "bin", "lib", "share" etc. subdirectories.
Eagerly awaiting.