Fix compiler warnings from unncessary abs (#162)

* Enhance AbsFunc specialization for signed and unsigned types

Refined the AbsFunc template struct to handle both signed and unsigned types using enable_if conditions. This change introduces specialized behavior, ensuring proper functioning and type safety depending on the numerical type.

* Add RPY_MAYBE_UNUSED to unused member variables

Marked unused member variables with RPY_MAYBE_UNUSED in comparison_trait.h and lie_key.cpp to avoid compiler warnings. This helps in maintaining cleaner code and ensures that warnings are handled properly.

platform/include/roughpy/generics/comparison_trait.h

@@ -28,7 +28,7 @@ class ConstRef;
  */
 class ROUGHPY_PLATFORM_EXPORT ComparisonTrait : public BuiltinTrait
 {
-    const Type* p_type;
+    RPY_MAYBE_UNUSED const Type* p_type;
 
 protected:
     constexpr explicit ComparisonTrait(const Type* type)

platform/include/roughpy/generics/number_trait.h

@@ -252,7 +252,7 @@ struct AbsFunc : NoSuchFunction {
 };
 
 template <typename T>
-struct AbsFunc<T, void_t<decltype(abs(declval<T>()))>> {
+struct AbsFunc<T, void_t<decltype(abs(declval<T>())), enable_if_t<is_signed_v<T>>>> {
     using result_t = decltype(abs(declval<T>()));
 
     static constexpr bool has_function = true;
@@ -263,6 +263,18 @@ struct AbsFunc<T, void_t<decltype(abs(declval<T>()))>> {
     }
 };
 
+template <typename T>
+struct AbsFunc<T, enable_if_t<is_unsigned_v<T>>>
+{
+    using result_t = T;
+    static constexpr bool has_function = true;
+    constexpr result_t operator()(const T& val) const
+    {
+        return val;
+    }
+};
+
+
 template <typename T, typename = void>
 struct SqrtFunc : NoSuchFunction {
 };

roughpy/src/algebra/lie_key.cpp

@@ -298,8 +298,8 @@ namespace {
 class ToLieKeyHelper
 {
     using container_type = typename python::PyLieKey::container_type;
-    dimn_t size;
-    dimn_t current;
+    RPY_MAYBE_UNUSED dimn_t size;
+    RPY_MAYBE_UNUSED dimn_t current;
     algebra::LieBasis basis;
     deg_t width;
     let_t max_letter = 0;