The cairo DLL in cairo-1.4.0-win32-only.zip is built with only the
win32 surface and font backends. It has no external non-system
dependencies.

The cairo DLL in cairo-1.4.0.zip includes also the SVG, PDF, PS and
PNG surface backends. It thus requires the libpng and zlib
distributions from the dependencies subfolder. It is not built with
the Freetype font backend, though.

The same name is used for the cairo DLL in all configurations. This is
on purpose.

GTK+ 2.10 requires cairo with the PDF backend (because of the printing
functionality). GTK+ 2.8 doesn't.

The cairo 1.4.0 developer zipfiles are otherwise identical, but
obviously the cairo-features.h file (which defines macros for each
included surface and font backend) is different.