merge gcc 4.8.2 r206687 (part 3).

branches: 1.1.2; 1.1.8;
pull across these new files from old gcc. from chuq.

Rebase to HEAD as of a few days ago.

sync with head.

for a reference, the tree before this commit was tagged
as yamt-pagecache-tag8.

this commit was splitted into small chunks to avoid
a limitation of cvs. ("Protocol error: too many arguments")