## Full example

    # Source: https://gn.googlesource.com/gn/+/main/docs/cross_compiles.md

    declare_args() {
      # Applies only to toolchains targeting target_cpu.
      sysroot = ""
    }

    config("my_config") {
      # Uses current_cpu because compile flags are toolchain-dependent.
      if (current_cpu == "arm") {
        defines = [ "CPU_IS_32_BIT" ]
      } else {
        defines = [ "CPU_IS_64_BIT" ]
      }
      # Compares current_cpu with target_cpu to see whether current_toolchain
      # has the same architecture as target_toolchain.
      if (sysroot != "" && current_cpu == target_cpu) {
        cflags = [
          "-isysroot",
          sysroot,
        ]
      }
    }