re PR c++/69688 (-Wsign-compare causes bogus error: size of array ‘uc_code’ is not an integral constant-expression)

	PR c++/69688
	* constexpr.c (clear_cv_and_fold_caches): Renamed from clear_cv_cache.
	Call clear_fold_cache.
	* cp-tree.h: Adjust declaration.
	* decl.c (finish_enum_value_list): Call clear_cv_and_fold_caches
	rather than clear_cv_cache and clear_fold_cache.
	* typeck2.c (store_init_value): Call clear_cv_and_fold_caches.

	* g++.dg/init/const12.C: New test.

From-SVN: r233220