If you haven't heard of LibreSSL it is a drop-in replacement for OpenSSL forked from OpenSSL and builds with CMake. Consider using LibreSSL before using OpenSSL with CMake.
It is just this easy:
target_link_libraries( MyTarget PRIVATE ssl crypto )
I've seen a number of solutions to getting OpenSSL built for iOS. I wanted a simple, standalone way of getting an OpenSSL library into an Xcode project without downloading pre-built binaries or adopting a dependency manager like Hunter.
Furthermore, getting CMake to not suck is pretty hard when it comes to building things outside of CMake's control. I had to go to a great amount of trouble to compile OpenSSL only when it updates, and check the servers each time. Generally speaking this means you cannot use anything but add_custom_command because the second you use ExternalProject_add or add_custom_target you end up with some undesirable features like always downloading and compiling.
If you want to reduce the number of architectures built you can define the OPENSSL_TARGET_ARCHITECTURES_${SDK} variables and list the specific architectures that should be built for each.
set( OPENSSL_TARGET_ARCHITECTURES_iphoneos arm64 )
set( OPENSSL_TARGET_ARCHITECTURES_iphonesimulator x86_64 )
You can adjust the version of OpenSSL built and define a SHA1 checksum with these variables
set( OPENSSL_URL "http://www.openssl.org/source/openssl-1.0.2-latest.tar.gz" )
set( OPENSSL_SHA1 "" )
- Checkout to openssl/
- mkdir openssl-build/
- cd openssl-build/
- cmake -GNinja ../openssl
- cmake --build .