Force merge conflicts?

Say, you create a branch of the ports tree to work on something
that touches a number of ports (like arrowd@'s current autotools-mandir
project).  You accumulate changes and bump PORTREVISION in various
port Makefiles.

Meanwhile work on the "main" branch continues and PORTREVISION also
gets bumped for entirely different reasons.

Now when you rebase/merge your changes into "main", git is happy
that the PORTREVISION line is the same in both branches and silently
unifies this.  Unfortunately, your incoming changes should _increment_
PORTREVISION, but that increment is now silently lost.

Is there a way to tell git to create a conflict when two branches
have the same change?

-- 
Christian "naddy" Weisgerber                          naddy@mips.inka.de