[boost] [shared_ptr] ia64 implementation by Ben Hutchings

The attached patch is a tested implementation for IA64 by Ben Hutchings. What should we do with it? a) add it to 1.33 b) add it to 1.33 but disable it by default c) ship 1.33 without it Opinions? Ben Hutchings wrote:

Here's a patch against current CVS that actually produces compliable code and passes the tests. It adds -D_REENTRANT to the command-line options in a gcc/ia64 multithreaded build because this is not implied by -pthread (see <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=10865>).