[Boost-build] Update based on difference instead of by timestamp

Subject: [Boost-build] Update based on difference instead of by timestamp
From: Phillip Seaver (phil_at_[hidden])
Date: 2015-07-14 09:09:23

I spent several hours chasing a bug that turned out to be using an older
version of a DLL.  It's under source control, so normally it gets copied
when the file gets updated.  In this case, however, the new version I
copied in had a timestamp earlier than the one copied by the install
target, so it never updated it.

Is there something in boost-build that would let me mark the file as
needing to be updated if it's different instead of the timestamp?  If
not, is there something I can use to force it to always copy?

Thanks,

Phillip