How to generate projects for Xcode

Several solutions in the last chapter utilize the libcurl library. For SSL support, this library needs to be linked with the OpenSSL library. Do the following to install OpenSSL:

1. Download the library from https://www.openssl.org/.
2. Unzip the archive and, in a terminal, go to its root directory.
3. Build and install the library with the following commands (executed in this order):
   
   ./Configure darwin64-x86_64-cc shared enable-ec_nistp_64_gcc_128 no-ssl2 no-ssl3 no-comp --openssldir=/usr/local/ssl/macos-x86_64
   
   make depend
   
   sudo make install

Until std::optional and the filesystem library will be available with Xcode's Clang, you need to use Boost. Do the following to install and build the Boost libraries:

1. Install Homebrew from https://brew.sh/.
2. Run the following command to download and install Boost automatically.
   
   brew install boost
3. After installation, the Boost library will be available at /usr/local/Cellar/boost/1.65.0.

In order to generate projects for Xcode from the sources you have to:

1. Open a terminal and go to the build directory in the source code root directory.
2. Execute the following CMake command:
   
   cmake -G Xcode .. -DOPENSSL_ROOT_DIR=/usr/local/bin -DOPENSSL_INCLUDE_DIR=/usr/local/include/ -DBUILD_TESTING=OFF -DBUILD_CURL_EXE=OFF -DUSE_MANUAL=OFF -DBOOST_FILESYSTEM=ON -DBOOST_OPTIONAL=ON -DBOOST_INCLUDE_DIR=/usr/local/Cellar/boost/1.65.0 -DBOOST_LIB_DIR=/usr/local/Cellar/boost/1.65.0/lib
3. After completion, the Xcode project can be found at build/cppchallenger.xcodeproj.