Add L suffix to __cpp_lib_char8_t value

	* include/bits/c++config.h (_cpp_lib_char8_t): Add L suffix to
	constant.
	* testsuite/experimental/feat-char8_t.cc: Likewise.

From-SVN: r269421

libstdc++-v3/ChangeLog

 2019-03-06  Jonathan Wakely  <jwakely@redhat.com>
 
+	* include/bits/c++config.h (_cpp_lib_char8_t): Add L suffix to
+	constant.
+	* testsuite/experimental/feat-char8_t.cc: Likewise.
+
 	 * include/std/type_traits [C++20] (is_bounded_array)
 	 (is_unbounded_array, is_bounded_array_v, is_unbounded_array_v):
 	 Define.

libstdc++-v3/include/bits/c++config

@@ -633,7 +633,7 @@ namespace std
 # endif
 #endif
 #ifdef _GLIBCXX_USE_CHAR8_T
-# define __cpp_lib_char8_t 201811
+# define __cpp_lib_char8_t 201811L
 #endif
 
 /* Define if __float128 is supported on this host. */

libstdc++-v3/testsuite/experimental/feat-char8_t.cc

@@ -12,6 +12,6 @@
 
 #ifndef  __cpp_lib_char8_t
 #  error "__cpp_lib_char8_t"
-#elif  __cpp_lib_char8_t != 201811
-#  error "__cpp_lib_char8_t != 201811"
+#elif  __cpp_lib_char8_t != 201811L
+#  error "__cpp_lib_char8_t != 201811L"
 #endif