* include/bits/c++config (_GLIBCXX14_USE_CONSTEXPR): Remove it.
	* include/bits/hashtable_policy.h (_Power2_rehash_policy::_M_next_bkt):
	Remove const qualification on function. Replace
	_GLIBCXX14_USE_CONSTEXPR on automatic variables with const.
	(_Power2_rehash_policy::_M_need_rehash): Remove const qualification.
	(_Power2_rehash_policy::_M_next_bkt): Remove mutable specifier.

From-SVN: r236697