A question on dynamic linking / version-changing libraries

[Michael]

On 2017-03-05, at 9:49 AM, Brandon Allbery <allbery.b at gmail.com> wrote:
> Also fixed-*path* libraries are part of the Mach-O format and the tooling does not exist to override this well...

Is this why a program compiled against a brew installation of qt5 in /usr/opt won't work with a ports installation of qt5 in /opt/local, and visa-versa?

Is there really no way around this -- no way to say "This program wants qt5 in whatever this system says is the local path of libraries"? No equivalent of $PATH for libraries?

... OK, is there any way - at all - to have a program compiled with either brew or ports that will run on an arbitrary OSX that might not have either? (i.e. -- fully built and contained)?