libstdc++: Fix constexpr memory algo tests for COW std::string

The old COW std::string is not usable in constant expressions, so these
new tests fail with -D_GLIBCXX_USE_CXX11_ABI=0.

The parts of the tests using std::string can be conditionally skipped.

libstdc++-v3/ChangeLog:

	* testsuite/20_util/specialized_algorithms/uninitialized_copy/constexpr.cc:
	Do not test COW std::string in constexpr contexts.
	* testsuite/20_util/specialized_algorithms/uninitialized_default_construct/constexpr.cc:
	Likewise.
	* testsuite/20_util/specialized_algorithms/uninitialized_fill/constexpr.cc:
	Likewise.
	* testsuite/20_util/specialized_algorithms/uninitialized_move/constexpr.cc:
	Likewise.
	* testsuite/20_util/specialized_algorithms/uninitialized_value_construct/constexpr.cc:
	Likewise.

Reviewed-by: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>

libstdc++-v3/testsuite/20_util/specialized_algorithms/uninitialized_copy/constexpr.cc

@@ -51,7 +51,9 @@ test01()
     test01_impl<char>({'a', 'b', 'c'}) &&
     test01_impl<int>({1, 2, 3, 4}) &&
     test01_impl<double>({1.0, 2.0, 3.0, 4.0}) &&
+#if _GLIBCXX_USE_CXX11_ABI
     test01_impl<std::string>({"a", "b", "cc", "dddd", "eeeeeeeeeeeeeeee"}) &&
+#endif
     test01_impl<std::vector<int>>({ {0}, {0, 1}, {0, 1, 2}});
 }
 

libstdc++-v3/testsuite/20_util/specialized_algorithms/uninitialized_default_construct/constexpr.cc

@@ -59,7 +59,9 @@ test01()
     test01_impl<char>() &&
     test01_impl<int>() &&
     test01_impl<double>() &&
+#if _GLIBCXX_USE_CXX11_ABI
     test01_impl<std::string>() &&
+#endif
     test01_impl<std::vector<int>>() &&
     test01_impl<std::unique_ptr<int>>();
 }

libstdc++-v3/testsuite/20_util/specialized_algorithms/uninitialized_fill/constexpr.cc

@@ -58,8 +58,10 @@ test01()
     test01_impl<int>(0) &&
     test01_impl<int>(42) &&
     test01_impl<double>(3.14) &&
+#if _GLIBCXX_USE_CXX11_ABI
     test01_impl<std::string>() &&
     test01_impl<std::string>(std::string("test")) &&
+#endif
     test01_impl<std::vector<int>>() &&
     test01_impl<std::vector<int>>({1, 2, 3, 4}) &&
     test01_impl<std::unique_ptr<int>>(nullptr);

libstdc++-v3/testsuite/20_util/specialized_algorithms/uninitialized_move/constexpr.cc

@@ -43,7 +43,9 @@ test01()
     test01_impl<char>({'a', 'b', 'c'}) &&
     test01_impl<int>({1, 2, 3, 4}) &&
     test01_impl<double>({1.0, 2.0, 3.0, 4.0}) &&
+#if _GLIBCXX_USE_CXX11_ABI
     test01_impl<std::string>({"a", "b", "cc", "dddd", "eeeeeeeeeeeeeeee"}) &&
+#endif
     test01_impl<std::vector<int>>({ {0}, {0, 1}, {0, 1, 2}}) &&
     test01_impl<std::unique_ptr<int>>(std::vector<std::unique_ptr<int>>(10));
 }

libstdc++-v3/testsuite/20_util/specialized_algorithms/uninitialized_value_construct/constexpr.cc

@@ -56,7 +56,9 @@ test01()
     test01_impl<char>() &&
     test01_impl<int>() &&
     test01_impl<double>() &&
+#if _GLIBCXX_USE_CXX11_ABI
     test01_impl<std::string>() &&
+#endif
     test01_impl<std::vector<int>>() &&
     test01_impl<std::unique_ptr<int>>();
 }