Replace libltdl with raw dlopen, dlsym

* NEWS: Update.
* am/bootstrap.am (SOURCES):
* module/Makefile.am (SOURCES): Add system/foreign-library.scm.
* configure.ac: Replace ltdl check with -ldl check.
* libguile/dynl.c: Rewrite to just expose core dlopen / dlsym / etc to a
  helper Scheme module.
  (scm_dynamic_link, scm_dynamic_pointer, scm_dynamic_function)
  (scm_dynamic_object_p, scm_dynamic_call): Rewrite in terms of (system
  foreign-library).
* libguile/extensions.c (load_extension): Avoid scm_dynamic_call.
* module/system/foreign-library.scm: New file.
* module/oop/goops.scm (<dynamic-object>): Hackily export
  <foreign-library> instead of a class here.
* doc/ref/api-foreign.texi (Foreign Function Interface): Rewrite to only
  document the new interfaces.  Eventually we will deprecate
  dynamic-link and friends.
* doc/ref/guile.texi (API Reference): Move Foreign Objects after Foreign
  Function Interface.  Seems there should be some closer relationship
  but this will do for now.
* doc/ref/tour.texi (Putting Extensions into Modules):
* doc/ref/libguile-parallel.texi (Parallel Installations): Update for
  rename of Modules and Extensions to Foreign Extensions.
* libguile/deprecated.h:
* libguile/deprecated.c (scm_dynamic_unlink): Deprecate.
* libguile/guile.c: Remove ltdl include.
* test-suite/tests/foreign.test: Update tests to use new API, and update
  error expectations.

1 files changed, 7 insertions, 2 deletions

diff --git a/module/oop/goops.scm b/module/oop/goops.scm
index df6df4f7b..9edc16b07 100644
--- a/module/oop/goops.scm
+++ b/module/oop/goops.scm
@@ -1,6 +1,6 @@
 ;;;; goops.scm -- The Guile Object-Oriented Programming System
 ;;;;
-;;;; Copyright (C) 1998-2003,2006,2009-2011,2013-2015,2017-2018
+;;;; Copyright (C) 1998-2003,2006,2009-2011,2013-2015,2017-2018,2021
 ;;;;   Free Software Foundation, Inc.
 ;;;; Copyright (C) 1993-1998 Erick Gallesio - I3S-CNRS/ESSI <eg@unice.fr>
 ;;;;
@@ -3307,10 +3307,15 @@ var{initargs}."
 (define <directory> (find-subclass <top> '<directory>))
 (define <array> (find-subclass <top> '<array>))
 (define <character-set> (find-subclass <top> '<character-set>))
-(define <dynamic-object> (find-subclass <top> '<dynamic-object>))
 (define <guardian> (find-subclass <applicable> '<guardian>))
 (define <macro> (find-subclass <top> '<macro>))
 
+;; <dynamic-object> used to be a SMOB type, albeit not exported even to
+;; C.  However now it's a record type, though still private.  Cross our
+;; fingers that nobody is using it in anger!
+(define <dynamic-object>
+  (module-ref (resolve-module '(system foreign-library)) '<foreign-library>))
+
 (define (define-class-subtree class)
   (define! (class-name class) class)
   (for-each define-class-subtree (class-direct-subclasses class)))