adding tcp_info support for MacOS

[bucweat]

PLEASE NOTE the following text from the iperf3 license. Submitting a
pull request to the iperf3 repository constitutes "[making]
Enhancements available...publicly":

You are under no obligation whatsoever to provide any bug fixes, patches, or
upgrades to the features, functionality or performance of the source code
("Enhancements") to anyone; however, if you choose to make your Enhancements
available either publicly, or directly to Lawrence Berkeley National
Laboratory, without imposing a separate written license agreement for such
Enhancements, then you hereby grant the following license: a non-exclusive,
royalty-free perpetual license to install, use, modify, prepare derivative
works, incorporate into other computer software, distribute, and sublicense
such enhancements or derivative works thereof, in binary and source code form.

The complete iperf3 license is available in the LICENSE file in the
top directory of the iperf3 source tree.

• Version of iperf3 (or development branch, such as master or
  3.1-STABLE) to which this pull request applies: master

• Issues fixed (if any): add tcp_info support for Mac OS (well really tcp_connection_info)

• Brief description of code changes (suitable for use as a commit message):
  add tcp_info support for Mac OS (well really tcp_connection_info)

[bucweat]

This is my first attempt at pull request here. I believe I made the necessary changes to support "tcp_info", but quite possible I missed something. It builds and runs here, and I get Retr column. I have not tried configure and build yet. Looking for more eyes to verify everything is valid hence pull request.

[bucweat]

fixes #1411

[davidBar-On]

Looking for more eyes to verify everything is valid hence pull request.

I don't have a way to test the changes, but except for two minor comments they look good to me.

[bucweat]

Looking for more eyes to verify everything is valid hence pull request.

I don't have a way to test the changes, but except for two minor comments they look good to me.

Thanks for the eyes on...and sorry for the turds...now [hopefully] removed.

Have you tried GitHub actions for building and testing?

[bucweat]

Have you tried GitHub actions for building and testing?

Never mind I see there is a build.yml. I had to update so I could trigger manually, but looks like everything is going green...at least in my fork. I guess you have the option to approve the build.yml workflow for this pull request...