rpath of some Moco libraries on Mac aren't being updated correctly

[carmichaelong]

I think I've isolated the issue to this if statement: https://github.com/opensim-org/opensim-core/blob/c76a63959c5c232262feeb2076a30aa55174f9e1/cmake/OpenSimMocoInstallMacDependencyLibraries.cmake.in#L62

Comparing the dependencies of the libcasadi_nlpsol_ipopt.dylib, libgfortran.dylib, and libquadmath.dylib shows differences between OpenSim 4.3's installer and the artifact from master branch. This seems to imply that for some reason the if (OPENSIM_WITH_CASADI) statement is not true at this point. @aymanhab is there any reason why at this point that OPENSIM_WITH_CASADI might not exist? Seems like there shouldn't be anything that different about these variables at install time?

[carmichaelong]

https://stackoverflow.com/questions/20792802/why-variables-are-not-accessed-inside-script-in-cmake