libsoup-gnome-9999 automake error CLEANFILES not defined

[jfkw]

libsoup-gnome-9999 ebuild at upstream f07043d989 fails with the following automake error:

***** automake *****
***** PWD: /var/tmp/portage/net-libs/libsoup-gnome-9999/work/libsoup-9999
***** automake --add-missing --copy --foreign

libsoup/Makefile.am:268: Cannot apply +=' becauseCLEANFILES' is not defined in
libsoup/Makefile.am:268: the following conditions:
libsoup/Makefile.am:268: !BUILD_LIBSOUP and HAVE_INTROSPECTION
libsoup/Makefile.am:268: Either define CLEANFILES' in these conditions, or use libsoup/Makefile.am:268:+=' in the same conditions as the definitions.