libremidi update to v5.4.3 and added virtual midi out as default

include/libremidi/config.hpp

@@ -1,11 +1,51 @@
 #pragma once
 
-#if defined(MSC_VER)
+#define LIBREMIDI_VERSION "5.4.3"
+
+// clang-format off
+#if !defined(LIBREMIDI_BASE_NAMESPACE)
+  #define LIBREMIDI_BASE_NAMESPACE libremidi
+#endif
+#if defined(LIBREMIDI_MODULE_BUILD)
+  #define LIBREMIDI_MODULE_EXPORT export
+  #define LIBREMIDI_MODULE_BEGIN_EXPORT export {
+  #define LIBREMIDI_MODULE_END_EXPORT }
+  #define NAMESPACE_LIBREMIDI export namespace LIBREMIDI_BASE_NAMESPACE
+  #define NAMESPACE_STDX export namespace stdx
+  #define LIBREMIDI_STATIC inline
+  #define LIBREMIDI_STATIC_IMPLEMENTATION inline
+  #define LIBREMIDI_STATIC_INLINE_IMPLEMENTATION inline
+  #define LIBREMIDI_INLINE_IMPLEMENTATION
+  #define LIBREMIDI_ANONYMOUS_NAMESPACE detail
+#else
+  #define LIBREMIDI_MODULE_EXPORT
+  #define LIBREMIDI_MODULE_BEGIN_EXPORT
+  #define LIBREMIDI_MODULE_END_EXPORT
+  #define NAMESPACE_LIBREMIDI namespace LIBREMIDI_BASE_NAMESPACE
+  #define NAMESPACE_STDX namespace stdx
+  #define LIBREMIDI_STATIC static inline
+
+#if defined(LIBREMIDI_HEADER_ONLY)
+  #define LIBREMIDI_STATIC_IMPLEMENTATION static
+  #define LIBREMIDI_STATIC_INLINE_IMPLEMENTATION static inline
+  #define LIBREMIDI_INLINE_IMPLEMENTATION inline
+#else
+  #define LIBREMIDI_STATIC_IMPLEMENTATION static
+  #define LIBREMIDI_STATIC_INLINE_IMPLEMENTATION static
+  #define LIBREMIDI_INLINE_IMPLEMENTATION
+#endif
+
+  #define LIBREMIDI_ANONYMOUS_NAMESPACE
+#endif
+// clang-format on
+
+#if defined(_MSC_VER)
   #define NOMINMAX 1
   #define WIN32_LEAN_AND_MEAN
 #endif
 
-#if defined(LIBREMIDI_EXPORTS)
+// Dynamic exports
+#if defined(LIBREMIDI_EXPORTS) || defined(LIBREMIDI_MODULE_BUILD)
   #if defined(_MSC_VER)
     #define LIBREMIDI_EXPORT __declspec(dllexport)
   #elif defined(__GNUC__) || defined(__clang__)
@@ -15,8 +55,7 @@
   #define LIBREMIDI_EXPORT
 #endif
 
-#define LIBREMIDI_VERSION "4.5.0"
-
+// Boost check to prevent ABI issues
 #if defined(LIBREMIDI_USE_BOOST)
   #if !__has_include(<boost/container/small_vector.hpp>)
     #error \
@@ -28,31 +67,77 @@
   #endif
 #endif
 
+// Use boost::small_vector if available
 #if __has_include(<boost/container/small_vector.hpp>) && !defined(LIBREMIDI_NO_BOOST)
-
   #if LIBREMIDI_SLIM_MESSAGE > 0
     #include <boost/container/static_vector.hpp>
-namespace libremidi
+NAMESPACE_LIBREMIDI
 {
 using midi_bytes = boost::container::static_vector<unsigned char, LIBREMIDI_SLIM_MESSAGE>;
 }
   #else
     #include <boost/container/small_vector.hpp>
-namespace libremidi
+NAMESPACE_LIBREMIDI
 {
-static constexpr int small_vector_minimum_size
+LIBREMIDI_STATIC constexpr int small_vector_minimum_size
     = sizeof(boost::container::small_vector<unsigned char, 1>);
 using midi_bytes = boost::container::small_vector<unsigned char, small_vector_minimum_size>;
 }
   #endif
 #else
   #include <vector>
-namespace libremidi
+NAMESPACE_LIBREMIDI
 {
 using midi_bytes = std::vector<unsigned char>;
 }
 #endif
 
+// Use boost::variant2 if available
+#define LIBREMIDI_NO_BOOST_VARIANT2 1
+#if __has_include(<boost/variant2.hpp>) && !defined(LIBREMIDI_NO_BOOST_VARIANT2)
+  #include <boost/variant2.hpp>
+  #define LIBREMIDI_VARIANT_IS_BOOST_VARIANT2
+namespace libremidi_variant_alias = boost::variant2;
+#endif
+
+#if !defined(LIBREMIDI_VARIANT_IS_BOOST_VARIANT2)
+  #include <variant>
+namespace libremidi_variant_alias = std;
+#endif
+
+namespace libremidi
+{
+using monostate = libremidi_variant_alias::monostate;
+template <typename T>
+concept nothrow_move_constructible = std::is_nothrow_move_constructible_v<T>;
+
+template <nothrow_move_constructible... Args>
+using variant = libremidi_variant_alias::variant<Args...>;
+
+template <typename... Args>
+using slow_variant = libremidi_variant_alias::variant<Args...>;
+
+template <std::size_t N, typename T>
+using variant_element = libremidi_variant_alias::variant_alternative<N, T>;
+template <std::size_t N, typename T>
+using variant_element_t = libremidi_variant_alias::variant_alternative_t<N, T>;
+
+using libremidi_variant_alias::operator==;
+using libremidi_variant_alias::operator!=;
+using libremidi_variant_alias::operator<;
+using libremidi_variant_alias::operator>;
+using libremidi_variant_alias::operator<=;
+using libremidi_variant_alias::operator>=;
+
+// using boost::variant2::in_place;
+// using libremidi_variant_alias::in_place;
+using libremidi_variant_alias::get;
+using libremidi_variant_alias::get_if;
+using libremidi_variant_alias::in_place_index;
+using libremidi_variant_alias::in_place_type;
+using libremidi_variant_alias::visit;
+}
+
 #if __has_include(<midi/universal_packet.h>) && defined(LIBREMIDI_USE_NI_MIDI2)
   #define LIBREMIDI_NI_MIDI2_COMPAT 1
 #endif
@@ -62,3 +147,9 @@ using midi_bytes = std::vector<unsigned char>;
 #else
   #define LIBREMIDI_INLINE
 #endif
+
+#if __cpp_contracts >= 202502L
+  #define LIBREMIDI_PRECONDITION(...) pre(__VA_ARGS__)
+#else
+  #define LIBREMIDI_PRECONDITION(...)
+#endif