Building OpenSSL for iOS has never been easier than with version 1.1.1. Required software for this purpose is a decent Mac with XCode and XCode command line tools installed. I have wrapped the build process into two shell scripts here and here. Download your version of OpenSSL 1.1.1 here and place the tarball you have downloaded alongside these two shell scripts in a directory on your mac. Then open a terminal, navigate into this directory and execute this in order to make the shell script executable:

chmod +x build.sh

At the time this post was written, version 1.1.1i of OpenSSL was the most recent version, so if you have downloaded a newer version than that, edit build.sh and locate line 4 which looks like this:

OPENSSLVERSION=openssl-1.1.1i

change the value of this string to the name of the OpenSSL tarball you have without the trailing ".tar.gz".

After that, execute the buildscript on the command line:

./build.sh

This will really take some time, be prepared for half an hour or longer. At the very end, you will get a subdirectory with a multiplatform version (i386, x86_64, armv7, armv7s, arm64) of libssl.a and libcrypto.a in the "build/lib" subdirectory. The subdirectory "build" also contains the relevant header files in individual subdirectories for the different platforms.

 The license for these shell scripts of mine is the same as for OpenSSL, so nothing should change for you.