Copying source code from libnbcompat vs. depending on it

["J. Lewis Muir" <jlmuir%imca-cat.org@localhost>]

Hello, All!

(I previously asked a similar question on the pkgsrc-users list, but
I didn't hear from anyone, so I'm trying tech-pkg now hoping it's the
right list.)

I'd like to understand the rationale behind including a private copy of
standard functions (e.g. vasprintf) in a package rather than using ones
provided by pkgtools/libnbcompat (i.e. libnbcompat.a).  Why do net/tnftp
and presumably other packages consider a private copy to be better?

Is it in the interest of portability and minimal dependencies?  If I
understand correctly, I think Alistair Crooks suggested this as his
feeling in [1] where he said the following:

  "I do not want to have to distribute libnbcompat with any code I
  write.  I also find requiring it to be present, just to compile stuff
  that I write, to be too onerous."

A downside is ending up with duplicate code, but maybe it's really
likely that the code is bug-free and unlikely to change, so it's fine.

I'd really appreciate hearing thoughts on this.

Thank you!

Lewis

[1] https://mail-index.netbsd.org/tech-userlevel/2015/11/02/msg009417.html