Using c-style defines with Swift Package Manager

When compiling the c-based library libmpdclient, I ran into the problem that it contains some #define statements which have to be set during the build. It took me while to find out how to set those when building the package with Swift Package Manager.

In the end off course the answer was right there in the documentation, but I only found that after watching one of the SPM videos from WWDC 2019.

let package = Package(
     name: "libmpdclient",
     targets: [
             name: "libmpdclient",
             publicHeadersPath: "mpd",
             cSettings: [
                 .define("DEFAULT_HOST", to: "\"localhost\""),
                 .define("DEFAULT_PORT", to: "6600"),
                 .define("ENABLE_TCP", to: "1")