Skip tests that depend on the cxx11 std::string

	* testsuite/21_strings/basic_string/init-list.cc:
	Require cxx11-abi.
	* testsuite/experimental/polymorphic_allocator/pmr_typedefs_match.cc:
	Likewise.
	* testsuite/experimental/polymorphic_allocator/pmr_typedefs_string.cc:
	Likewise.

From-SVN: r263800

libstdc++-v3/ChangeLog

 2018-08-23  Jonathan Wakely  <jwakely@redhat.com>
 
+	* testsuite/21_strings/basic_string/init-list.cc:
+	Require cxx11-abi.
+	* testsuite/experimental/polymorphic_allocator/pmr_typedefs_match.cc:
+	Likewise.
+	* testsuite/experimental/polymorphic_allocator/pmr_typedefs_string.cc:
+	Likewise.
+
 	* testsuite/23_containers/deque/capacity/max_size.cc: Fix test for
 	C++98 mode.
 	* testsuite/23_containers/deque/modifiers/assign/1.cc: Likewise.

libstdc++-v3/testsuite/21_strings/basic_string/init-list.cc

@@ -17,6 +17,7 @@
 //
 
 // { dg-do run { target c++11 } }
+// { dg-require-effective-target cxx11-abi }
 
 #include <testsuite_hooks.h>
 

libstdc++-v3/testsuite/experimental/polymorphic_allocator/pmr_typedefs_match.cc

@@ -16,6 +16,7 @@
 // <http://www.gnu.org/licenses/>.
 
 // { dg-do compile { target c++14 } }
+// { dg-require-effective-target cxx11-abi }
 
 #include <experimental/regex>
 

libstdc++-v3/testsuite/experimental/polymorphic_allocator/pmr_typedefs_string.cc

@@ -16,6 +16,7 @@
 // <http://www.gnu.org/licenses/>.
 
 // { dg-do compile { target c++14 } }
+// { dg-require-effective-target cxx11-abi }
 
 #include <experimental/string>