Workaround for incompatible between libstdc++ consteval based std::is…

…_constant_evaluated implementation and clang-14+

Signed-off-by: Vladislav Shchapov <[email protected]>

include/fmt/core.h

@@ -329,7 +329,14 @@ template <typename... T> FMT_CONSTEXPR void ignore_unused(const T&...) {}
 
 constexpr FMT_INLINE auto is_constant_evaluated(
     bool default_value = false) noexcept -> bool {
-#ifdef __cpp_lib_is_constant_evaluated
+// Workaround for incompatible between libstdc++ consteval based
+// std::is_constant_evaluated implementation and clang-14+.
+// https://github.com/fmtlib/fmt/issues/3247
+#if FMT_CPLUSPLUS >= 202002L && defined(_GLIBCXX_RELEASE) && \
+    _GLIBCXX_RELEASE >= 12 && FMT_CLANG_VERSION >= 14
+  ignore_unused(default_value);
+  return __builtin_is_constant_evaluated();
+#elif defined(__cpp_lib_is_constant_evaluated)
   ignore_unused(default_value);
   return std::is_constant_evaluated();
 #else