[cairo] gtkmm on Win32

[Tor Lillqvist]

> No. My doubt is, if the error is so serious that the application has
> to terminate (in debug mode win32) how can it continue to work without
> any complaints in release mode (again win32).

Small heap corruptions (like a one byte overrun) can have effects
exactly like that. They can work fine on one platform or configuration
but crash (at some point much later than when the actual corruption
happens) on others.

--tml