* autogen.sh: Try to continue even if we don't have gtk-doc
installed; this will obviously won't work if you don't pass
--disable-docs --disable-gtk-doc to autogen.sh as well.
* autogen.sh: Clean up a bit
* clutter/clutter-fixed.[ch]:
(clutter_double_to_fixed),
(clutter_double_to_int),
(clutter_double_to_uint): Make these functions public, as they
are expanded by their respective macros. This fixes the errors
from the linker trying to resolve their name.