lex.c (lex_string): Add -Wc++11-compat warning.

libcpp/
	* lex.c (lex_string): Add -Wc++11-compat warning.
	* include/cpplib.h: Add CPP_W_CXX11_COMPAT.
	(struct cpp_options): Add cpp_warn_cxx11_compat.
	* init.c (cpp_create_reader): Initialize it.
gcc/c-family/
	* c.opt (Wc++0x-compat): Set it.

From-SVN: r222961
diff --git a/libcpp/include/cpplib.h b/libcpp/include/cpplib.h
index 5e08014..0152ec8 100644
--- a/libcpp/include/cpplib.h
+++ b/libcpp/include/cpplib.h
@@ -484,6 +484,9 @@
   /* True if warn about differences between C90 and C99.  */
   signed char cpp_warn_c90_c99_compat;
 
+  /* True if warn about differences between C++98 and C++11.  */
+  bool cpp_warn_cxx11_compat;
+
   /* Dependency generation.  */
   struct
   {
@@ -960,7 +963,8 @@
   CPP_W_LITERAL_SUFFIX,
   CPP_W_DATE_TIME,
   CPP_W_PEDANTIC,
-  CPP_W_C90_C99_COMPAT
+  CPP_W_C90_C99_COMPAT,
+  CPP_W_CXX11_COMPAT
 };
 
 /* Output a diagnostic of some kind.  */