upstream ABI changes

[Jeff Johnson]

During the final stages of LSB 4.1, devchk was used to look at function
prototype mismatched. A few are being discovered which indicate ABI changes -
if the function takes a different return type.

These will be added here, and really can't be changed until it's possible to
track the change in the database - the subject of bug 3119.

It would be useful if people who know these items well could comment on whether
there's actually been a change, or if it's something we missed somehow earlier
and is our mistake.

extern void xmlPushInput(xmlParserCtxtPtr, xmlParserInputPtr);
vs. Upstream:
extern int xmlPushInput(xmlParserCtxtPtr, xmlParserInputPtr);

extern void cairo_ft_scaled_font_lock_face(cairo_scaled_font_t *);
vs. Upstream:
extern FT_Face cairo_ft_scaled_font_lock_face (cairo_scaled_font_t *);