No, I didn't get any warnings that .h file not found.

Well, that's odd. Line 91 simply contains:

     XTransform xtransform;
[download]

which is certainly not a syntax error if a header file that defines the XTransform type was found. And Google doesn't return anything for "cairo-xlib-surface-private.h:91".

I think Joost is right :-)

Cheers,
Rob