How can I install a MacPorts port that is linked with an earlier MacOS release?

[Mojca Miklavec]

Dear Michael,

On Wed, 13 Mar 2019 at 16:03, Michael A. Leonetti wrote:
>
> How an I install the port packages that support El Capitan (or any specific
> MacOS version) and above to link against?

By far the least painful way would be to install El Capitan inside a
VM and build there.

The other option would be to contribute patches to provide better
support for doing these kind of builds (which would in fact be
useful). You can ask MacPorts to do universal builds, you can ask it
to link against a different SDK etc., but it mostly lacks better
support for building for an older OS. When I tried to do some
bootstrapping for 10.5 on 10.6 one of the biggest issue was that the
ports sometimes use code that is only executed on a particular OS
version. Even if you set the environmental variables to link against
an older SDK, define the variable for the target OS etc. ... you might
still be bitten by those if-else parts of the code that check what
your current OS is, not the OS you want to target.

Personally I would welcome patches to fix that, but that would
probably take quite some effort.

Mojca