[Xr] Obvious libpixregion configure.in fix

[Keith Packard]

Around 19 o'clock on Apr 22, Carl Worth wrote:

> I know Keith shoved a new flag into libtool 1.5 for directly setting
> version information. Is that a recommended approach for new libraries
> or is it only important to maintain compatibility with non-libtool
> library versioning?

You should use -version-info unless you need to keep compatible shared 
library versions for existing libraries.  Fontconfig was able to use 
-version-info because it's minor version number was zero, but Xft uses 
-version-number as it's version number is 2.1.

I'm no longer maintaining imake build mechanisms for Xrender, Xft, or 
fontconfig; one build system is plenty.

I'm pretty happy with how fontconfig is set up to use automake; Noah 
Levitt did Xft and Xrender, so he may have additional suggestions on what 
would make things even better.

-keith