Work around leak in boost flat_set

Summary: This is very likely to be the memory leak reported to be new in
HHVM 3.4. See code comment and linked GitHub issue for full explanation.

Fixes https://github.com/facebook/hhvm/issues/4268

{sync, type="child", parent="internal", parentrevid="1736543", parentrevfbid="1584241511789266", parentdiffid="5935230"}

Reviewed By: @paulbiss

Differential Revision: D1736543
Try not to rely on $USER

Summary: There are rare cases when it might not be set -- at least one
person complained in IRC of a crash due to this. Instead, try the
$LOGNAME env var, which apparently POSIX specifies should be set, and if
that doesn't work, run the `logname` command. cf:
http://unix.stackexchange.com/questions/76354/who-sets-user-and-username-environment-variables

Reviewed By: @int3

Differential Revision: D1731369

Signature: t1:1731369:1418322898:1688cb39c77b574dbf4ec3119bdead8be013fadd
Formatting fixes.

Summary: Mostly fixes for lines > 80. I have my editor set to wrap lines so
it's kind of annoying.

Reviewed By: @jwatzman

Differential Revision: D1732663

Signature: t1:1732663:1418424495:8551b7528dedf2fba8b62476befced0d315cc40e
Remove unused cache.ml

Reviewed By: @jwatzman

Differential Revision: D1732842

Signature: t1:1732842:1418424718:e29935c3321d75673ef3f1749fc64805c13f72cb
Add a couple of license headers.

Reviewed By: @jwatzman

Differential Revision: D1732831

Signature: t1:1732831:1418424578:eaac1f1e31ad188b8910625f8a22debe90f5d284