As with the Linux build, use ./bootstrap, ./configure, and make.
If you used Homebrew to install a supported version of OpenSSL,
you may need to include its path in PKG_CONFIG_PATH.
OS X compilers treat uninitialized global variables as
common symbols,
which can be eliminated with the -fno-common compiler option.
Future updates to the autotools configurations may automate one or both of these steps.
./bootstrap
PKG_CONFIG_PATH="/usr/local/opt/openssl/lib/pkgconfig" EXTRA_CFLAGS=-fno-common ./configure
make