c++: vector of class with bool ctor [PR108195]

c++: vector of class with bool ctor [PR108195]

The transformation done by r13-4564 to use the iterator constructor instead
of the initializer-list constructor breaks if the iterator pointers are
themselves treated as elements of an initializer-list, so check for that.

	PR c++/108195

gcc/cp/ChangeLog:

	* call.cc (build_user_type_conversion_1): Check whether the
	iterators also find a list ctor.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp0x/initlist-vect2.C: New test.