provide log option to top-level build

Capture stdout/stderr for later diagnostics.

Mentioned in commit 166abf70ba6e8c1eea04cb7d0300f44ddcf969a2

Mentioned in commit 9548a2764d170f7747353ca64cb993d1f1277099

Mentioned in commit 50a5c6295b5c92d01a2c4f3d48f0b747dd74f62a

Mentioned in issue #357 (closed)

Status changed to closed