Libcpp has c8 rtomb mbrtoc8 experimental 2

libcxx/include/__config

@@ -1027,6 +1027,8 @@ typedef __char32_t char32_t;
 #    else
 #      define _LIBCPP_HAS_C8RTOMB_MBRTOC8 0
 #    endif
+#  elif defined(__clang__)
+#    define _LIBCPP_HAS_C8RTOMB_MBRTOC8 1
 #  else
 #    define _LIBCPP_HAS_C8RTOMB_MBRTOC8 0
 #  endif

libcxx/test/std/depr/depr.c.headers/uchar_h.compile.pass.cpp

@@ -23,11 +23,6 @@
 // __STDC_UTF_16__ may or may not be defined by the C standard library
 // __STDC_UTF_32__ may or may not be defined by the C standard library
 
-#if !defined(TEST_HAS_NO_C8RTOMB_MBRTOC8)
-ASSERT_SAME_TYPE(size_t, decltype(mbrtoc8((char8_t*)0, (const char*)0, (size_t)0, (mbstate_t*)0)));
-ASSERT_SAME_TYPE(size_t, decltype(c8rtomb((char*)0, (char8_t)0, (mbstate_t*)0)));
-#endif
-
 ASSERT_SAME_TYPE(size_t, decltype(mbrtoc16((char16_t*)0, (const char*)0, (size_t)0, (mbstate_t*)0)));
 ASSERT_SAME_TYPE(size_t, decltype(c16rtomb((char*)0, (char16_t)0, (mbstate_t*)0)));
 

libcxx/test/std/depr/depr.c.headers/uchar_h_char8_t.compile.pass.cpp

@@ -0,0 +1,24 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03
+
+// The following platforms do not provide mbrtoc8 and c8rtomb so the tests fail
+// XFAIL: target={{.+}}-aix{{.*}}
+// XFAIL: android
+// XFAIL: darwin
+// XFAIL: freebsd
+// XFAIL: windows
+// XFAIL: LIBCXX-PICOLIBC-FIXME
+
+// <uchar.h>
+
+#include <uchar.h>
+
+ASSERT_SAME_TYPE(size_t, decltype(mbrtoc8((char8_t*)0, (const char*)0, (size_t)0, (mbstate_t*)0)));
+ASSERT_SAME_TYPE(size_t, decltype(c8rtomb((char*)0, (char8_t)0, (mbstate_t*)0)));

libcxx/test/std/strings/c.strings/cuchar.compile.pass.cpp

@@ -23,11 +23,6 @@
 // __STDC_UTF_16__ may or may not be defined by the C standard library
 // __STDC_UTF_32__ may or may not be defined by the C standard library
 
-#if !defined(TEST_HAS_NO_C8RTOMB_MBRTOC8)
-ASSERT_SAME_TYPE(std::size_t, decltype(std::mbrtoc8((char8_t*)0, (const char*)0, (size_t)0, (mbstate_t*)0)));
-ASSERT_SAME_TYPE(std::size_t, decltype(std::c8rtomb((char*)0, (char8_t)0, (mbstate_t*)0)));
-#endif
-
 ASSERT_SAME_TYPE(std::size_t, decltype(std::mbrtoc16((char16_t*)0, (const char*)0, (size_t)0, (mbstate_t*)0)));
 ASSERT_SAME_TYPE(std::size_t, decltype(std::c16rtomb((char*)0, (char16_t)0, (mbstate_t*)0)));
 

libcxx/test/std/strings/c.strings/cuchar_char8_t.compile.pass.cpp

@@ -0,0 +1,24 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03
+
+// The following platforms do not provide mbrtoc8 and c8rtomb so the tests fail
+// XFAIL: target={{.+}}-aix{{.*}}
+// XFAIL: android
+// XFAIL: darwin
+// XFAIL: freebsd
+// XFAIL: windows
+// XFAIL: LIBCXX-PICOLIBC-FIXME
+
+// <cuchar>
+
+#include <cuchar>
+
+ASSERT_SAME_TYPE(std::size_t, decltype(std::mbrtoc8((char8_t*)0, (const char*)0, (size_t)0, (mbstate_t*)0)));
+ASSERT_SAME_TYPE(std::size_t, decltype(std::c8rtomb((char*)0, (char8_t)0, (mbstate_t*)0)));