with the versions in this module using
scm_c_extend_primitive_generic.
* goops.scm (equal?): Define default method.
* goops.c (scm_primitive_generic_generic): Enable primitive
generic if not enabled.
(scm_sys_goops_loaded): Setup unextended primitive generics.
* goops.c, goops.h (scm_c_extend_primitive_generic): New function.
* snarf.h (SCM_PRIMITIVE_GENERIC, SCM_PRIMITIVE_GENERIC_1): New
snarf macros.
* numbers.c (scm_abs): Use SCM_PRIMITIVE_GENERIC. (This is only a
testing example. All uses of SCM_GPROC should be converted.)
* procprop.c (scm_stand_in_scm_proc): Use scm_assq instead of
scm_assoc.
* eq.c (scm_equal_p): Turned into a primitive generic.
