Re: Emacs contributions, C and Lisp

[Jacob Bachmeyer <jcb62281@gmail.com>]

Richard Stallman wrote:
> [[[ To any NSA and FBI agents reading my email: please consider    ]]]
> [[[ whether defending the US Constitution against all enemies,     ]]]
> [[[ foreign or domestic, requires you to follow Snowden's example. ]]]
>
>   > It has been a while since I last read through the FSF GPL FAQs on this, 
>   > so maybe copyright has been weakened, but I thought that dynamic linking 
>   > does not avoid the GPL.
>
> Our position is that dynamic linking makes a combination covered by
> the GPL -- provided the code _as distributed_ is designed for linking
> the parts together.
>
> Combinations that the user decides to make, which are not prearranged
> by code that gets distributed, are not limited by the GPL.  This is
> true regardless of how the parts get linked.
>   

Where is the line here?  Does having GPL code define a new API mean that 
programs using that new API can be considered designed for linking to 
that GPL code?  If not, how can the GPL be effective on libraries, such 
as Readline?  I thought that this was how that worked.

More specifically, if a future version of GCC, buildable as a Guile 
extension, offers access to its AST through a Guile API, would nonfree 
programs be able to use the GCC API, or would the GPL protections cover 
GCC's API?  Assume that GCC invents its own API and does not reimplement 
some other API for AST access.  If nonfree programs could use GCC in 
this case, what prevents the same abuse of Readline now?  (I base my 
longer-term proposal for Emacs/Guile/GCC on past positions I have seen 
taken with respect to Readline; perhaps I have misunderstood.)