heap: use pragma once if available

git-svn-id: http://svn.boost.org/svn/boost/trunk@86525 b8fc166d-592f-0410-95f2-cb63ce0dd405
heap: possible fix for testsuite

git-svn-id: http://svn.boost.org/svn/boost/trunk@86526 b8fc166d-592f-0410-95f2-cb63ce0dd405
Direct dependency on /boost//headers is needed to trigger forward header generation.

git-svn-id: http://svn.boost.org/svn/boost/trunk@86527 b8fc166d-592f-0410-95f2-cb63ce0dd405
[geometry] Add doc/src/examples to top-level Jamfile.v2 and doc/Jamfile.v2

git-svn-id: http://svn.boost.org/svn/boost/trunk@86528 b8fc166d-592f-0410-95f2-cb63ce0dd405