Export libc++ exceptions (#5390)

* Export libc++ exceptions

* Remove emscripten limit

* Remove __apple_build_version__ condition from PYBIND11_EXPORT_EXCEPTION

* Add a comment

include/pybind11/detail/common.h

@@ -164,14 +164,6 @@
 #    endif
 #endif
 
-#if !defined(PYBIND11_EXPORT_EXCEPTION)
-#    if defined(__apple_build_version__)
-#        define PYBIND11_EXPORT_EXCEPTION PYBIND11_EXPORT
-#    else
-#        define PYBIND11_EXPORT_EXCEPTION
-#    endif
-#endif
-
 // For CUDA, GCC7, GCC8:
 // PYBIND11_NOINLINE_FORCED is incompatible with `-Wattributes -Werror`.
 // When defining PYBIND11_NOINLINE_FORCED, it is best to also use `-Wno-attributes`.
@@ -329,6 +321,17 @@ PYBIND11_WARNING_POP
 #    endif
 #endif
 
+// For libc++, the exceptions should be exported,
+// otherwise, the exception translation would be incorrect.
+// IMPORTANT: This code block must stay BELOW the #include <exception> above (see PR #5390).
+#if !defined(PYBIND11_EXPORT_EXCEPTION)
+#    if defined(_LIBCPP_EXCEPTION)
+#        define PYBIND11_EXPORT_EXCEPTION PYBIND11_EXPORT
+#    else
+#        define PYBIND11_EXPORT_EXCEPTION
+#    endif
+#endif
+
 // Must be after including <version> or one of the other headers specified by the standard
 #if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
 #    define PYBIND11_HAS_U8STRING

tests/test_exceptions.py

@@ -76,7 +76,7 @@ def test_cross_module_exceptions(msg):
 
 # TODO: FIXME
 @pytest.mark.xfail(
-    "env.MACOS and (env.PYPY or pybind11_tests.compiler_info.startswith('Homebrew Clang')) or sys.platform.startswith('emscripten')",
+    "env.MACOS and env.PYPY",
     raises=RuntimeError,
     reason="See Issue #2847, PR #2999, PR #4324",
 )