2008-10-18  Douglas Gregor  <doug.gregor@gmail.com>

	* include/bits/stl_pair.h (__may_be_null_pointer_init): New.
	(pair::pair): Eliminate the redundant pair(U1&&, U2&&) constructor.
	Add lvalue pair<U1, U2> constructor to handle non-const pair lvalues.
	Remove the old variadic constructor, and instead provide several
	variadic constructors that avoid failing when attempting to
	initialize a pointer from a null pointer constant.
	* testsuite/20_util/pair/moveable.cc (test3): Add new tests with
	initialization of pointers from the null pointer constant.

From-SVN: r141214