Shove kicad2step into pcbnew itself with a new cli

thirdparty/argparse/samples/parse_known_args.cpp

@@ -0,0 +1,26 @@
+#include <argparse/argparse.hpp>
+#include <cassert>
+
+int main(int argc, char *argv[]) {
+  argparse::ArgumentParser program("test");
+  program.add_argument("--foo").implicit_value(true).default_value(false);
+  program.add_argument("bar");
+
+  auto unknown_args = program.parse_known_args(argc, argv);
+
+  if (program.is_used("--foo")) {
+    std::cout << "--foo        : " << program.get<bool>("--foo") << "\n";
+  }
+
+  if (program.is_used("bar")) {
+    std::cout << "bar          : " << program.get<std::string>("bar") << "\n";
+  }
+
+  if (!unknown_args.empty()) {
+    std::cout << "Unknown args : ";
+    for (const auto &u : unknown_args) {
+      std::cout << u << " ";
+    }
+    std::cout << std::endl;
+  }
+}