[jit] Merger of trunk r215958 into jit branch

[David Malcolm]

I've merged today's svn trunk into the git branch
dmalcolm/jit, pushing it as
81d39bf76e3ffd4e62c307cc8d22df18572eec19

Specifically, this is from trunk r215958 aka
e012cdc775868e9922f5fef9068a764546876d93
bringing in all changes since 215803 aka
68874c5d021dd6b8b740ffd23960e46e333270b5 (2014-10-02)

[am continuing to experiment with embedding the driver in-process within
the jit library, and wanted r215861 as part of that]