Coapp doesn't work with older MacOS

[paulrouget]

A user feedback

_Your new version of VDH Versión 8.1.0.0a5 does NOT work in my Mac x86-64 with Mozilla Firefox 115.3.1.

The message when attempting download is 'auxiliar app is requiered'. Then, a URL is pointed to proceed to download the mentioned 'auxiliar app' -in its last version-.

Once having selected three of the different 'auxiliar app' versions suposedly compatible with my engine, and done the installation the resultant message is 'an error ocurred'._

[jcfrog]

A new feedback from user:

Returning to the previous versions of VDH and Aux APP, it seems that those old versions works OK again.

For your know and further considerations... :

This is a Mac OS X Sierra, version 10.12.6. 3m GHz Intel Core i, 16 GB 2134 MHz DDR4 RAM... surfing with Mozilla Firefox 115.3 1esr (64 bit).

[paulrouget]

We need to set the MacOS target to something lower. I'm gonna try to put my hand on a MacOS Sierra machine and see what can be done.

 ./vdhcoapp --info
dyld: lazy symbol binding failed: Symbol not found: ____chkstk_darwin
  Referenced from: /Applications/net.downloadhelper.coapp.app/Contents/MacOS/./vdhcoapp
  Expected in: /usr/lib/libSystem.B.dylib

[paulrouget]

I gave it a try. For now, I'm putting that on hold. The issue is that we can't build anything on Sierra as the operating system is not supported by homebrew and all.

The only solution I see is setting the targetted Framework version to a lower value at compile time (ffmpeg & node), but I don't know how to do this yet.

[julianclem]

also see #190 regarding system requirements on the download page