[gnu.org #432927] Can a Windows installer include both VC++ libs and GPLed libs?

[John W. Eaton]

On  8-May-2009, Brett Smith via RT wrote:

| The reason the GPL works this way is because we need to keep the System
| Library exception very narrow.  If we make it too easy for libraries to
| qualify as System Libraries, it will become feasible for companies to
| change free software and keep the changes proprietary by putting them in
| a "System Library."  The language that prevents System Libraries from
| being distributed alongside the software helps prevent this sort of abuse.

| > If that is a GPL violation, does it depend strictly on the installer
| > being an executable, or would it also apply to a .zip or .tar.gz
| > installer (e.g., a compressed archive that contains an installation
| > program and many packages to install, including the VC++ library
| > installer executable)?
| 
| No.  Distributing the Octave binaries and the runtime libraries on the
| same media would be problematic, regardless of the specific medium used.
| 
| I think the Windows binary distribution should simply provide users with
| instructions to obtain the libraries from Microsoft's site.  I realize
| that's inconvenient, but hopefully it's not too bad, and I think it's a
| worthwhile change to avoid any GPL trouble.

Hi Brett,

This recommendation surprises me because it seems that if you allow
(and even encourage) distributors to instruct their users to download
the VC++ libraries, then you would have to allow it for any other
"System Libraries" as well, and that would allow someone to do the
thing you want to prevent (change free software and keep the changes
proprietary by putting them in a "System Library").  The only
restriction then would be that the "System Library" could not be
distributed on the same media, but could be distributed separately.
To me, that seems like asking for abuses.

Several people have brought up the idea of performing the download and
installation of the libraries automatically instead of simply
providing instructions.  What about that?  Is it OK?  If not, why not?
Why would it be OK to tell someone how to perform the installation but
not OK to provide a method to do the job more or less automatically?

In any case, I would really prefer it for the primary Windows binaries
for Octave to be built with the MinGW compiler.

Thanks,

jwe