SCM ifaces = scm_cdr (scm_assoc (ly_symbol2scm ("interfaces"), meta));
for (SCM s = ifaces; scm_is_pair (s); s = scm_cdr (s))
{
SCM ifaces = scm_cdr (scm_assoc (ly_symbol2scm ("interfaces"), meta));
for (SCM s = ifaces; scm_is_pair (s); s = scm_cdr (s))
{