caf: Should use MacPorts openssl

[ryandesign (Ryan Carsten Schmidt)]

​https://build.macports.org/builders/ports-10.13_x86_64-builder/builds/88215/steps/install-port/logs/stdio

-- Found OpenSSL: //usr/lib/libcrypto.dylib (found version "1.1.1g")  
CMake Error at CMakeLists.txt:625 (message):
  failed to compile/link against OpenSSL

This should probably be using MacPorts openssl instead.

[Schamschula (Marius Schamschula)]

Yes. The project home page didn't list any dependencies other than cmake (and Pthread). I didn't notice, as my machine picked up the MacPorts version. I assume libressl should also work, but my build machine only has openssl installed, and I can't test that.

Now, it looks like caf is also looking for curl by default and finding the version in the SDK. Unfortunately, it looks like cmake isn't finding the MacPorts version, even when given hints using configure.args. Hence, I've disabled building curl examples.

[Schamschula (Marius Schamschula)]

In 548425e5f289e4f67e221a1db396f319009c6dac/macports-ports (master):

caf: add openssl dependency, disable curl examples

Closes: #60897
drop to compiler.cxx_standard 2011, as that's what cmake requests