No more concept of "pure generics"

* libguile/goops.h (SCM_PUREGENERICP, SCM_VALIDATE_PUREGENERIC)
  (SCM_VTABLE_FLAG_GOOPS_PURE_GENERIC, SCM_CLASSF_PURE_GENERIC):
  Remove.
* libguile/goops.c (scm_set_primitive_generic_x): Use SCM_GENERICP, not
  SCM_PUREGENERICP.
  (scm_sys_bless_pure_generic_vtable_x): Remove; this flag isn't
  checked.

* module/oop/goops.scm: Don't call %bless-pure-generic-vtable!; there's
  no need.

module/oop/goops.scm

@@ -530,26 +530,20 @@
   (n-specialized #:init-value 0)
   (extended-by #:init-value ())
   effective-methods)
-(%bless-pure-generic-vtable! <generic>)
 (define-standard-class <extended-generic> (<generic>)
   #:metaclass <applicable-struct-class>
   (extends #:init-value ()))
-(%bless-pure-generic-vtable! <extended-generic>)
 (define-standard-class <generic-with-setter> (<generic>
                                               <applicable-struct-with-setter>)
   #:metaclass <applicable-struct-with-setter-class>)
-(%bless-pure-generic-vtable! <generic-with-setter>)
 (define-standard-class <accessor> (<generic-with-setter>)
   #:metaclass <applicable-struct-with-setter-class>)
-(%bless-pure-generic-vtable! <accessor>)
 (define-standard-class <extended-generic-with-setter> (<extended-generic>
                                                        <generic-with-setter>)
   #:metaclass <applicable-struct-with-setter-class>)
-(%bless-pure-generic-vtable! <extended-generic-with-setter>)
 (define-standard-class <extended-accessor> (<accessor>
                                             <extended-generic-with-setter>)
   #:metaclass <applicable-struct-with-setter-class>)
-(%bless-pure-generic-vtable! <extended-accessor>)
 
 ;; Methods
 (define-standard-class <method> (<object>)