2018-07-06  François Dumont  <fdumont@gcc.gnu.org>

	* include/debug/functions.h (__gnu_debug::__check_string): Move...
	* include/debug/string (__gnu_debug::__check_string): ... here.
	(_GLIBCXX_DEBUG_VERIFY_STR_COND_AT): New.
	(__glibcxx_check_string_n_constructor): New.
	(__gnu_debug::basic_string<>(const _CharT*, size_type, const _Alloc&)):
	Use latter.
	(__glibcxx_check_string_constructor): New.
	(__gnu_debug::basic_string<>(const _CharT*, const _Alloc&)):
	Use latter.
	* testsuite/21_strings/basic_string/debug/1_neg.cc: New.
	* testsuite/21_strings/basic_string/debug/2_neg.cc: New.

From-SVN: r262480