glr2.cc: add an example

Currently this example crashes on input such as "T (x) + y;".
The same example with glr.c works properly.

* examples/c++/glr/Makefile, examples/c++/glr/README.md,
* examples/c++/glr/c++-types.test, examples/c++/glr/c++-types.yy,
* examples/c++/glr/local.mk, examples/c++/local.mk: New.
Based on examples/c/glr/c++-types.y.

data/skeletons/glr2.cc

@@ -2092,7 +2092,7 @@ public:
               {
                 state_set_index yynewStack = yystateStack.yysplitStack (yyk);
                 YY_DEBUG_STREAM << "Splitting off stack " << yynewStack.get()
-                                << " from " << yyk.get();
+                                << " from " << yyk.get() << '\n';
                 YYRESULTTAG yyflag =
                   yyglrReduce (yynewStack, *yyconflicts,
                                yyimmediate[*yyconflicts]);