macosx_deployment_target - building for previous versions from MacOS 10.13

[Jeffrey Walton]

On Fri, Sep 4, 2020 at 6:54 AM Friedrich Beckmann
<friedrich.beckmann at gmx.de> wrote:
>
> ...
> I just figured out that ncurses indeed does not build for deployment target 10.5 because macports or whoever sets the CXXFLAGS to

Sorry to hear this. Ncurses is a mess. I cringe when it is needed...
No source code repo, bizarre processes and procedures, memory leaks
out the ass, ...

Are you fetching their patches per
https://invisible-island.net/ncurses/ncurses.faq.html#applying_patches?

> :debug:configure CXXFLAGS='-pipe -Os -stdlib=libc++ -arch x86_64 -arch i386‘

Be careful of this. It assumes all packages are fat/universal safe.
That is not the case. For example, OpenSSL is not fat safe because of
different configuration files depending on the platform, and the way
it wields the AR command.

You need to do something like https://stackoverflow.com/q/25530429.
You build the library for each platform, rig up some header files, and
use lipo to combine your output artifacts.

Jeff