I'm jhbuilding gnome-vfs from CVS HEAD, and it stops on the following warnings because of -Werror:

gnome-vfs-volume-ops.c: In function `spawn_mount':
gnome-vfs-volume-ops.c:429: warning: passing arg 1 of `gnome_vfs_pty_open' from incompatible pointer type
gnome-vfs-volume-ops.c:518: warning: implicit declaration of function `kill'
gnome-vfs-volume-ops.c:518: warning: nested extern declaration of `kill'

The first can be fixed with a (pid_t *) cast in the first argument of the function call on line 426, as it's a GPid *, not a pid_t * as the definition states. The second can be fixed by #include <signal.h> at the top.

Further on there's:
xdgmimemagic.c: In function `_xdg_mime_magic_parse_magic_line':
xdgmimemagic.c:475: warning: unused variable `i'

which occurs because SPARC is big endian and the code that uses i is wrapped by #if LITTLE_ENDIAN.

Full build log at http://jhbuild.bxlug.be/builds/2006-05-01-0003/logs/gnome-vfs/#build (may appear blank towards the bottom in gecko-based browsers, just view source).