cpplex.c (cpp_interpret_charconst): Get signedness or otherwise of wide character constants correct.

	* cpplex.c (cpp_interpret_charconst): Get signedness or
	otherwise of wide character constants correct.
	* cppexp.c (lex): Get signedness of wide charconsts correct.
	* testsuite/gcc.dg/cpp/wchar-1.c: New test.

From-SVN: r50005