[libc++][nfc] Add TEST_HAS_NO_FILESYSTEM_LIBRARY.

[Mordante]

Summary

This avoids using an libc++ internal macro in our tests.

libcxx/test/std/iterators/iterator.primitives/iterator.traits/cxx20_iterator_traits.compile.pass.cpp

 #include "test_macros.h"
 
 #ifndef TEST_HAS_NO_LOCALIZATION
 #  include <regex>
 #  include <ostream>
 #  include <istream>
 #endif
 
-#ifndef _LIBCPP_HAS_NO_FILESYSTEM_LIBRARY
-# include <filesystem>
+#ifndef TEST_HAS_NO_FILESYSTEM_LIBRARY
+#  include <filesystem>
 #endif
 
-#include "test_macros.h"
 #include "test_iterators.h"
 #include "iterator_traits_cpp17_iterators.h"
 
 template <class Traits>
 constexpr bool has_iterator_concept_v = requires {
   typename Traits::iterator_concept;
 };
 

 static_assert(testWithoutConcept<std::istreambuf_iterator<char>, char, long long, char, char*, std::input_iterator_tag>());
 static_assert(testWithoutConcept<std::move_iterator<int*>, int, std::ptrdiff_t, int&&, int*, std::random_access_iterator_tag>());
 static_assert(testIOIterator<std::ostream_iterator<int, char>, std::output_iterator_tag>());
 static_assert(testIOIterator<std::ostreambuf_iterator<int, char>, std::output_iterator_tag>());
 static_assert(testConstWithoutConcept<std::cregex_iterator, std::cmatch, std::forward_iterator_tag>());
 static_assert(testConstWithoutConcept<std::cregex_token_iterator, std::csub_match, std::forward_iterator_tag>());
 #endif // !TEST_HAS_NO_LOCALIZATION
 
-#ifndef _LIBCPP_HAS_NO_FILESYSTEM_LIBRARY
+#ifndef TEST_HAS_NO_FILESYSTEM_LIBRARY
 static_assert(testWithoutConcept<std::filesystem::directory_iterator, std::filesystem::directory_entry, std::ptrdiff_t,
                                  const std::filesystem::directory_entry&, const std::filesystem::directory_entry*,
                                  std::input_iterator_tag>());
 static_assert(testWithoutConcept<std::filesystem::recursive_directory_iterator, std::filesystem::directory_entry,
                                  std::ptrdiff_t, const std::filesystem::directory_entry&,
                                  const std::filesystem::directory_entry*, std::input_iterator_tag>());
 #endif
 

libcxx/test/std/utilities/format/format.formatter/format.formatter.spec/types.compile.pass.cpp

 
 #include <array>
 #include <bitset>
 #include <bitset>
 #include <chrono>
 #include <complex>
 #include <concepts>
 #include <deque>
-#ifndef _LIBCPP_HAS_NO_FILESYSTEM_LIBRARY
-#  include <filesystem>
-#endif
 #include <format>
 #include <forward_list>
 #include <list>
 #include <memory>
 #include <map>
 #include <optional>
 #include <queue>
 #include <set>
 #include <stack>
 #include <span>
 #include <tuple>
 #include <type_traits>
 #include <unordered_map>
 #include <unordered_set>
 #include <valarray>
 #include <variant>
 
 #include "test_macros.h"
 
+#ifndef TEST_HAS_NO_FILESYSTEM_LIBRARY
+#  include <filesystem>
+#endif
 #ifndef TEST_HAS_NO_LOCALIZATION
 #  include <regex>
 #endif
 #ifndef TEST_HAS_NO_THREADS
 #  include <thread>
 #endif
 
 // Validate default template argument.

 // The paper hasn't been voted in so currently all formatters are disabled.
 // TODO validate whether the test is correct after the paper has been accepted.
 template <class CharT>
 void test_P1636() {
   assert_formatter_is_disabled<std::basic_streambuf<CharT>, CharT>();
   assert_formatter_is_disabled<std::bitset<42>, CharT>();
   assert_formatter_is_disabled<std::complex<double>, CharT>();
   assert_formatter_is_disabled<std::error_code, CharT>();
-#ifndef _LIBCPP_HAS_NO_FILESYSTEM_LIBRARY
+#ifndef TEST_HAS_NO_FILESYSTEM_LIBRARY
   assert_formatter_is_disabled<std::filesystem::path, CharT>();
 #endif
   assert_formatter_is_disabled<std::shared_ptr<int>, CharT>();
 #ifndef TEST_HAS_NO_LOCALIZATION
   assert_formatter_is_disabled<std::sub_match<CharT*>, CharT>();
 #endif
 #ifndef TEST_HAS_NO_THREADS
   assert_formatter_is_disabled<std::thread::id, CharT>();

libcxx/test/support/test_macros.h

 #if TEST_STD_VER <= 17 || !defined(__cpp_char8_t)
 #  define TEST_HAS_NO_CHAR8_T
 #endif
 
 #if defined(_LIBCPP_HAS_NO_THREADS)
 #  define TEST_HAS_NO_THREADS
 #endif
 
+#if defined(_LIBCPP_HAS_NO_FILESYSTEM_LIBRARY)
+#  define TEST_HAS_NO_FILESYSTEM_LIBRARY
+#endif
+
 #if defined(__GNUC__)
 #pragma GCC diagnostic pop
 #endif
 
 #endif // SUPPORT_TEST_MACROS_HPP