Hello,

I was helping out "ablephar`" on IRC and they found that setting a
file property `header-args:C++` does not work.

After some edebug magic, I discovered that org has a feature that lets
you append property values! (Not the best way to discover a great
feature, I must say! :-)

The fix could either be a documentation fix. (I would've tried using
cpp instead of C++, if I knew that was supported). But, this would
still have some users seeing things broken and then looking up docs or
trying out the alternative.

OR

a "hacky" fix, (better for the users ?), could be to consider KEY+ to
be indicating appending, but KEY++ to not.  Thoughts?


Thanks,
Puneeth