Re: linking small programs with AC_LINK_IFELSE

[Ralf Wildenhues]

* Bob Rossi wrote on Thu, Jan 18, 2007 at 09:54:24PM CET:
> 
> Well, lets say I modified libexpat and it's now different than the one
> on the system.
[...]
> However, if for some reason the local expat build fails, my check to 
> compile a small program still works because it picks up the installed 
> one on the system.

So add a symbol to your modified libexpat.  Link against that symbol in
your source code.  Use -no-undefined.  Then programs will fail to link
(and on some systems, those where -no-undefined works well, also
libraries will fail to link).  Of course you've broken the API now.

Hope that helps.

Cheers,
Ralf