libstdc++: Fix tests that fail with -fno-char8_t

Adjust expected errors or skip tests as UNSUPPORTED if -fno-char8_t is
used in the test flags.

libstdc++-v3/ChangeLog:

	* testsuite/20_util/integer_comparisons/equal_neg.cc: Use
	no-opts selector for errors that depend on -fchar8_t.
	* testsuite/20_util/integer_comparisons/greater_equal_neg.cc:
	Likewise.
	* testsuite/20_util/integer_comparisons/greater_neg.cc:
	Likewise.
	* testsuite/20_util/integer_comparisons/in_range_neg.cc:
	Likewise.
	* testsuite/20_util/integer_comparisons/less_equal_neg.cc:
	Likewise.
	* testsuite/20_util/integer_comparisons/less_neg.cc: Likewise.
	* testsuite/20_util/integer_comparisons/not_equal_neg.cc:
	Likewise.
	* testsuite/21_strings/basic_string/hash/hash_char8_t.cc: Skip
	if -fno-char8_t is used.
	* testsuite/21_strings/headers/cuchar/functions_std_cxx20.cc:
	Likewise.
	* testsuite/27_io/basic_ostream/inserters_character/char/deleted.cc:
	Likewise.
	* testsuite/27_io/basic_ostream/inserters_character/wchar_t/deleted.cc:
	Likewise.
	* testsuite/27_io/filesystem/path/factory/u8path-depr.cc: Use
	char for u8 literal if char8_t is not available.
	* testsuite/27_io/headers/iosfwd/synopsis.cc: Check
	__cpp_char8_t.
	* testsuite/29_atomics/atomic_integral/wait_notify.cc: Likewise.
	* testsuite/29_atomics/headers/atomic/types_std_c++20_neg.cc:
	Remove check for _GLIBCXX_USE_CHAR8_T.

libstdc++-v3/testsuite/20_util/integer_comparisons/equal_neg.cc

@@ -25,8 +25,8 @@ bool c = std::cmp_equal(2, L'2'); // { dg-error "here" }
 bool d = std::cmp_equal(L'2', 2); // { dg-error "here" }
 bool e = std::cmp_equal(true, 1); // { dg-error "here" }
 bool f = std::cmp_equal(0, false); // { dg-error "here" }
-bool g = std::cmp_equal(97, u8'a'); // { dg-error "here" }
-bool h = std::cmp_equal(u8'a', 97); // { dg-error "here" }
+bool g = std::cmp_equal(97, u8'a'); // { dg-error "here" "" { target { no-opts "-fno-char8_t" } } }
+bool h = std::cmp_equal(u8'a', 97); // { dg-error "here" "" { target { no-opts "-fno-char8_t" } } }
 bool i = std::cmp_equal(97, u'a'); // { dg-error "here" }
 bool j = std::cmp_equal(u'a', 97); // { dg-error "here" }
 bool k = std::cmp_equal(97, U'a'); // { dg-error "here" }

libstdc++-v3/testsuite/20_util/integer_comparisons/greater_equal_neg.cc

@@ -25,8 +25,8 @@ bool c = std::cmp_greater_equal(2, L'2'); // { dg-error "constexpr" }
 bool d = std::cmp_greater_equal(L'2', 2); // { dg-error "constexpr" }
 bool e = std::cmp_greater_equal(true, 1); // { dg-error "constexpr" }
 bool f = std::cmp_greater_equal(0, false); // { dg-error "constexpr" }
-bool g = std::cmp_greater_equal(97, u8'a'); // { dg-error "constexpr" }
-bool h = std::cmp_greater_equal(u8'a', 97); // { dg-error "constexpr" }
+bool g = std::cmp_greater_equal(97, u8'a'); // { dg-error "constexpr" "" { target { no-opts "-fno-char8_t" } } }
+bool h = std::cmp_greater_equal(u8'a', 97); // { dg-error "constexpr" "" { target { no-opts "-fno-char8_t" } } }
 bool i = std::cmp_greater_equal(97, u'a'); // { dg-error "constexpr" }
 bool j = std::cmp_greater_equal(u'a', 97); // { dg-error "constexpr" }
 bool k = std::cmp_greater_equal(97, U'a'); // { dg-error "constexpr" }

libstdc++-v3/testsuite/20_util/integer_comparisons/greater_neg.cc

@@ -25,8 +25,8 @@ bool c = std::cmp_greater(2, L'2'); // { dg-error "constexpr" }
 bool d = std::cmp_greater(L'2', 2); // { dg-error "constexpr" }
 bool e = std::cmp_greater(true, 1); // { dg-error "constexpr" }
 bool f = std::cmp_greater(0, false); // { dg-error "constexpr" }
-bool g = std::cmp_greater(97, u8'a'); // { dg-error "constexpr" }
-bool h = std::cmp_greater(u8'a', 97); // { dg-error "constexpr" }
+bool g = std::cmp_greater(97, u8'a'); // { dg-error "constexpr" "" { target { no-opts "-fno-char8_t" } } }
+bool h = std::cmp_greater(u8'a', 97); // { dg-error "constexpr" "" { target { no-opts "-fno-char8_t" } } }
 bool i = std::cmp_greater(97, u'a'); // { dg-error "constexpr" }
 bool j = std::cmp_greater(u'a', 97); // { dg-error "constexpr" }
 bool k = std::cmp_greater(97, U'a'); // { dg-error "constexpr" }

libstdc++-v3/testsuite/20_util/integer_comparisons/in_range_neg.cc

@@ -25,8 +25,10 @@ bool c = std::in_range<int>(L'2'); // { dg-error "here" }
 bool d = std::in_range<wchar_t>(2); // { dg-error "here" }
 bool e = std::in_range<int>(true); // { dg-error "here" }
 bool f = std::in_range<bool>(0); // { dg-error "here" }
-bool g = std::in_range<int>(u8'a'); // { dg-error "here" }
-bool h = std::in_range<char8_t>(97); // { dg-error "here" }
+bool g = std::in_range<int>(u8'a'); // { dg-error "here" "" { target { no-opts "-fno-char8_t" } } }
+#ifdef __cpp_char8_t
+bool h = std::in_range<char8_t>(97); // { dg-error "here" "" { target { no-opts "-fno-char8_t" } } }
+#endif
 bool i = std::in_range<int>(u'a'); // { dg-error "here" }
 bool j = std::in_range<char16_t>(97); // { dg-error "here" }
 bool k = std::in_range<int>(U'a'); // { dg-error "here" }

libstdc++-v3/testsuite/20_util/integer_comparisons/less_equal_neg.cc

@@ -25,8 +25,8 @@ bool c = std::cmp_less_equal(2, L'2'); // { dg-error "constexpr" }
 bool d = std::cmp_less_equal(L'2', 2); // { dg-error "constexpr" }
 bool e = std::cmp_less_equal(true, 1); // { dg-error "constexpr" }
 bool f = std::cmp_less_equal(0, false); // { dg-error "constexpr" }
-bool g = std::cmp_less_equal(97, u8'a'); // { dg-error "constexpr" }
-bool h = std::cmp_less_equal(u8'a', 97); // { dg-error "constexpr" }
+bool g = std::cmp_less_equal(97, u8'a'); // { dg-error "constexpr" "" { target { no-opts "-fno-char8_t" } } }
+bool h = std::cmp_less_equal(u8'a', 97); // { dg-error "constexpr" "" { target { no-opts "-fno-char8_t" } } }
 bool i = std::cmp_less_equal(97, u'a'); // { dg-error "constexpr" }
 bool j = std::cmp_less_equal(u'a', 97); // { dg-error "constexpr" }
 bool k = std::cmp_less_equal(97, U'a'); // { dg-error "constexpr" }

libstdc++-v3/testsuite/20_util/integer_comparisons/less_neg.cc

@@ -25,8 +25,8 @@ bool c = std::cmp_less(2, L'2'); // { dg-error "here" }
 bool d = std::cmp_less(L'2', 2); // { dg-error "here" }
 bool e = std::cmp_less(true, 1); // { dg-error "here" }
 bool f = std::cmp_less(0, false); // { dg-error "here" }
-bool g = std::cmp_less(97, u8'a'); // { dg-error "here" }
-bool h = std::cmp_less(u8'a', 97); // { dg-error "here" }
+bool g = std::cmp_less(97, u8'a'); // { dg-error "here" "" { target { no-opts "-fno-char8_t" } } }
+bool h = std::cmp_less(u8'a', 97); // { dg-error "here" "" { target { no-opts "-fno-char8_t" } } }
 bool i = std::cmp_less(97, u'a'); // { dg-error "here" }
 bool j = std::cmp_less(u'a', 97); // { dg-error "here" }
 bool k = std::cmp_less(97, U'a'); // { dg-error "here" }

libstdc++-v3/testsuite/20_util/integer_comparisons/not_equal_neg.cc

@@ -25,8 +25,8 @@ bool c = std::cmp_equal(2, L'2'); // { dg-error "here" }
 bool d = std::cmp_equal(L'2', 2); // { dg-error "here" }
 bool e = std::cmp_equal(true, 1); // { dg-error "here" }
 bool f = std::cmp_equal(0, false); // { dg-error "here" }
-bool g = std::cmp_equal(97, u8'a'); // { dg-error "here" }
-bool h = std::cmp_equal(u8'a', 97); // { dg-error "here" }
+bool g = std::cmp_equal(97, u8'a'); // { dg-error "here" "" { target { no-opts "-fno-char8_t" } } }
+bool h = std::cmp_equal(u8'a', 97); // { dg-error "here" "" { target { no-opts "-fno-char8_t" } } }
 bool i = std::cmp_equal(97, u'a'); // { dg-error "here" }
 bool j = std::cmp_equal(u'a', 97); // { dg-error "here" }
 bool k = std::cmp_equal(97, U'a'); // { dg-error "here" }

libstdc++-v3/testsuite/21_strings/basic_string/hash/hash_char8_t.cc

@@ -16,6 +16,7 @@
 // <http://www.gnu.org/licenses/>.
 
 // { dg-do run { target c++20 } }
+// { dg-skip-if "" { *-*-* } { "-fno-char8_t" } }
 
 #include <string>
 #include <memory_resource>

libstdc++-v3/testsuite/21_strings/headers/cuchar/functions_std_cxx20.cc

@@ -1,4 +1,5 @@
 // { dg-do compile { target c++20 } }
+// { dg-skip-if "" { *-*-* } { "-fno-char8_t" } }
 
 #include <cuchar>
 

libstdc++-v3/testsuite/27_io/basic_ostream/inserters_character/char/deleted.cc

@@ -20,6 +20,7 @@
 // Test character inserters defined as deleted by P1423.
 
 // { dg-do compile { target c++20 } }
+// { dg-skip-if "" { *-*-* } { "-fno-char8_t" } }
 
 #include <ostream>
 

libstdc++-v3/testsuite/27_io/basic_ostream/inserters_character/wchar_t/deleted.cc

@@ -20,6 +20,7 @@
 // Test wide character inserters defined as deleted by P1423.
 
 // { dg-do compile { target c++20 } }
+// { dg-skip-if "" { *-*-* } { "-fno-char8_t" } }
 
 #include <ostream>
 

libstdc++-v3/testsuite/27_io/filesystem/path/factory/u8path-depr.cc

@@ -10,6 +10,8 @@ auto p2 = fs::u8path(s, s); // { dg-warning "deprecated" }
 
 #if __cpp_lib_char8_t
 const char8_t* u = u8"";
+#else
+const char* u = u8"";
+#endif
 auto p3 = fs::u8path(u); // { dg-warning "deprecated" }
 auto p4 = fs::u8path(u, u); // { dg-warning "deprecated" }
-#endif

libstdc++-v3/testsuite/27_io/headers/iosfwd/synopsis.cc

@@ -9,7 +9,7 @@ namespace std
 
   template<class charT> struct char_traits;
   template<> struct char_traits<char>;
-#if __cplusplus >= 202002L
+#if __cplusplus >= 202002L && defined __cpp_char8_t
   template<> struct char_traits<char8_t>;
 #endif
 #if __cplusplus >= 201103L

libstdc++-v3/testsuite/29_atomics/atomic_integral/wait_notify.cc

@@ -59,7 +59,9 @@ main ()
   check<unsigned long long>();
 
   check<wchar_t>();
+#if __cpp_char8_t
   check<char8_t>();
+#endif
   check<char16_t>();
   check<char32_t>();
 

libstdc++-v3/testsuite/29_atomics/headers/atomic/types_std_c++20_neg.cc

@@ -47,9 +47,7 @@ void test01()
   using atomic_llong;		// { dg-error "expected nested-name-specifier" }
   using atomic_ullong;		// { dg-error "expected nested-name-specifier" }
   using atomic_wchar_t;		// { dg-error "expected nested-name-specifier" }
-#ifdef _GLIBCXX_USE_CHAR8_T
   using atomic_char8_t;		// { dg-error "expected nested-name-specifier" }
-#endif
   using atomic_char16_t;	// { dg-error "expected nested-name-specifier" }
   using atomic_char32_t;	// { dg-error "expected nested-name-specifier" }