[cairo] Making cairo_error weak

[Billy Biggs]

Keith Packard (keithp at keithp.com):

> On Wed, 2005-08-17 at 03:50 -0400, Behdad Esfahbod wrote:
> 
> > All I really want is to be able to get a message printed when I'm
> > developing something with Cairo.  
> 
> If we consider cairo errors as bugs in applications, we should have
> the error function print out a message by default.

   ... and then you'll need API to be able to shut it off when
necessary (due to bugs in cairo).

  -Billy