Switch from C++1z to C++17; corresponds to r319688 in Clang.

llvm-svn: 319694
diff --git a/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusNameParser.cpp b/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusNameParser.cpp
index 88bdd68..aebea6a 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusNameParser.cpp
+++ b/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusNameParser.cpp
@@ -628,7 +628,7 @@
     g_options.CPlusPlus = true;
     g_options.CPlusPlus11 = true;
     g_options.CPlusPlus14 = true;
-    g_options.CPlusPlus1z = true;
+    g_options.CPlusPlus17 = true;
   });
   return g_options;
 }