mac and ssl/openssl

[Riccardo Mottola]

Hi all!

tangent question for mac development and different MacOS versions.

Old versions of macs which I use, like 10.4 up to 10.7 have openssl and 
ssl.h

I tested that 10.13 doesn't have, so GNUMail doesn't compile.

Did Mac switch to a different ssl version and/or changed the location of 
it? with which version?
Do you have experience supporting it?
I'd like to keep GNUMail working on vintage macs, but also support newer 
ones.

Riccardo