maths: remove duplicate equality test helpers

maths.hpp

@@ -50,33 +50,11 @@ namespace cruft {
     // Useful for explictly ignore equality warnings
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wfloat-equal"
-    template <typename Ta, typename Tb>
-    constexpr
-    typename std::enable_if_t<
-        std::is_arithmetic<Ta>::value &&
-        std::is_arithmetic<Tb>::value,
-        bool
-    >
-    equal (const Ta &a, const Tb &b)
+    template <typename ValueA, typename ValueB>
+    constexpr auto
+    equal (ValueA const &a, ValueB const &b)
     {
-        // use double not to force conversion for types with explicit bool
-        // operators on the result of equality
-        return !!(a == b);
-    }
-
-    //-------------------------------------------------------------------------
-    template <typename Ta, typename Tb>
-    inline
-    typename std::enable_if_t<
-        !std::is_arithmetic<Ta>::value ||
-        !std::is_arithmetic<Tb>::value,
-        bool
-    >
-    equal  (const Ta &a, const Tb &b)
-    {
-        // use double not to force conversion for types with explicit bool
-        // operators on the result of equality
-        return !!(a == b);
+        return a == b;
     }
 #pragma GCC diagnostic pop