merge [85122],[85123],[85124] from trunk to release; fixes #7915, fixes #8850, fixes #8262

git-svn-id: http://svn.boost.org/svn/boost/branches/release@85424 b8fc166d-592f-0410-95f2-cb63ce0dd405
update mergeinfo

git-svn-id: http://svn.boost.org/svn/boost/branches/release@85425 b8fc166d-592f-0410-95f2-cb63ce0dd405
merge [84937] from trunk, fixes #8759

git-svn-id: http://svn.boost.org/svn/boost/branches/release@85426 b8fc166d-592f-0410-95f2-cb63ce0dd405
merge [85118],[85119],[85120],[85121] from trunk; fixes #8843, fixes #8880, fixes #8882, fixes #8474

git-svn-id: http://svn.boost.org/svn/boost/branches/release@85427 b8fc166d-592f-0410-95f2-cb63ce0dd405