[wpiutil] Add Drake and Drake JNI (#2613)

Drake is a collection of tools for analyzing robot dynamics and building control systems.
See https://drake.mit.edu/ for details.

Co-authored-by: Tyler Veness <calcmogul@gmail.com>

wpiutil/src/test/native/include/drake/common/unused.h

@@ -0,0 +1,53 @@
+#pragma once
+
+namespace drake {
+
+/// Documents the argument(s) as unused, placating GCC's -Wunused-parameter
+/// warning.  This can be called within function bodies to mark that certain
+/// parameters are unused.
+///
+/// When possible, removing the unused parameter is better than placating the
+/// warning.  However, in some cases the parameter is part of a virtual API or
+/// template concept that is used elsewhere, so we can't remove it.  In those
+/// cases, this function might be an appropriate work-around.
+///
+/// Here's rough advice on how to fix Wunused-parameter warnings:
+///
+/// (1) If the parameter can be removed entirely, prefer that as the first
+///     choice.  (This may not be possible if, e.g., a method must match some
+///     virtual API or template concept.)
+///
+/// (2) Unless the parameter name has acute value, prefer to omit the name of
+///     the parameter, leaving only the type, e.g.
+/// @code
+/// void Print(const State& state) override { /* No state to print. */ }
+/// @endcode
+///     changes to
+/// @code
+/// void Print(const State&) override { /* No state to print. */}
+/// @endcode
+///     This no longer triggers the warning and further makes it clear that a
+///     parameter required by the API is definitively unused in the function.
+///
+///     This is an especially good solution in the context of method
+///     definitions (vs declarations); the parameter name used in a definition
+///     is entirely irrelevant to Doxygen and most readers.
+///
+/// (3) When leaving the parameter name intact has acute value, it is
+///     acceptable to keep the name and mark it `unused`.  For example, when
+///     the name appears as part of a virtual method's base class declaration,
+///     the name is used by Doxygen to document the method, e.g.,
+/// @code
+/// /** Sets the default State of a System.  This default implementation is to
+///     set all zeros.  Subclasses may override to use non-zero defaults.  The
+///     custom defaults may be based on the given @p context, when relevant.  */
+/// virtual void SetDefault(const Context<T>& context, State<T>* state) const {
+///   unused(context);
+///   state->SetZero();
+/// }
+/// @endcode
+///
+template <typename ... Args>
+void unused(const Args& ...) {}
+
+}  // namespace drake