Linkage of GPLed GCC to Closed Source via XML or Perl

[Joe Buck]

> I'm a bit afraid the whole discussion here is quite irrelevant; such an
> interface allowing to use gcc with a proprietary back-end already exist (and
> ALWAYS existed): You just use GCC to generate assembly language, then
> assemble this through a proprietary assembler!... For a long time it was the
> ONLY way to use GCC on a lot of machines!

That's always been allowed.  People are also free to, in effect, add
proprietary front ends for other languages by producing programs that
generate C.  Adding new interfaces to GCC to make it easier to add
proprietary backends is another matter.  While there may be legal ways
to accomplish this, the official GCC policy is not to cooperate with
such efforts.