Where are the header files & libraries of the OpenSSL package that comes with macOS?

Question

I just installed macOS Catalina version 10.15.4 (19E287).

It comes with OpenSSL (well actually LibreSSL) installed.

$ openssl version
LibreSSL 2.6.5

I'm installing PostgreSQL from source "with support for SSL (encrypted) connections", by supplying the --with-openssl command line option to configure.

--with-openssl

    Build with support for SSL (encrypted) connections. This
    requires the OpenSSL package to be installed. "configure" will
    check for the required header files and libraries to make sure
    that your OpenSSL installation is sufficient before proceeding.

So where do I tell the compiler to look for the "required header files and libraries"?

Ie, what do I put for the --with-includes and --with-libraries command line options to configure?

--with-includes=DIRECTORIES

    "DIRECTORIES" is a colon-separated list of directories that will
    be added to the list the compiler searches for header files. If
    you have optional packages (such as GNU Readline) installed in a
    non-standard location, you have to use this option and probably
    also the corresponding "--with-libraries" option.

    Example: --with-includes=/opt/gnu/include:/usr/sup/include.

--with-libraries=DIRECTORIES

    "DIRECTORIES" is a colon-separated list of directories to search
    for libraries. You will probably have to use this option (and
    the corresponding "--with-includes" option) if you have packages
    installed in non-standard locations.

    Example: --with-libraries=/opt/gnu/lib:/usr/sup/lib.

I don't want to use Homebrew. I'd rather install LibreSSL from source if I must.

Answer 1

They are not present anymore because it has been deprecated. Either you inckudde your own library or if you want to link against macOS own libraries (libssl & libcrypto) you should use the corresponding header files for this version. You can find the sources from Apple here.