Shove kicad2step into pcbnew itself with a new cli

thirdparty/argparse/samples/positional_argument.cpp

@@ -0,0 +1,28 @@
+#include <argparse/argparse.hpp>
+
+int main(int argc, char *argv[]) {
+  argparse::ArgumentParser program("main");
+
+  program.add_argument("square")
+      .help("display the square of a given number")
+      .scan<'i', int>();
+
+  program.add_argument("--verbose").default_value(false).implicit_value(true);
+
+  try {
+    program.parse_args(argc, argv);
+  } catch (const std::runtime_error &err) {
+    std::cerr << err.what() << std::endl;
+    std::cerr << program;
+    std::exit(1);
+  }
+
+  int input = program.get<int>("square");
+
+  if (program["--verbose"] == true) {
+    std::cout << "The square of " << input << " is " << (input * input)
+              << std::endl;
+  } else {
+    std::cout << (input * input) << std::endl;
+  }
+}