any->u8vector and family now implemented in Scheme

* module/Makefile.am:
* module/srfi/srfi-4/gnu.scm: New module, for extensions to srfi-4.
  Currently defines the any->FOOvector family.

* libguile/srfi-4.c:
* libguile/srfi-4.i.c: Dispatch scm_any_to_FOOvector calls to the
  scheme-implemented functions in (srfi srfi-4 gnu).

module/srfi/srfi-4/gnu.scm

@@ -0,0 +1,52 @@
+;;; Extensions to SRFI-4
+
+;; 	Copyright (C) 2001, 2002, 2004, 2006, 2009 Free Software Foundation, Inc.
+;;
+;; This library is free software; you can redistribute it and/or
+;; modify it under the terms of the GNU Lesser General Public
+;; License as published by the Free Software Foundation; either
+;; version 3 of the License, or (at your option) any later version.
+;; 
+;; This library is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+;; Lesser General Public License for more details.
+;; 
+;; You should have received a copy of the GNU Lesser General Public
+;; License along with this library; if not, write to the Free Software
+;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+
+;;; Commentary:
+
+;; Extensions to SRFI-4. Fully documented in the Guile Reference Manual.
+
+;;; Code:
+
+(define-module (srfi srfi-4 gnu)
+  #:use-module (srfi srfi-4)
+  #:export (;; Somewhat polymorphic conversions.
+            any->u8vector any->s8vector any->u16vector any->s16vector
+            any->u32vector any->s32vector any->u64vector any->s64vector
+            any->f32vector any->f64vector any->c32vector any->c64vector))
+
+
+(define-macro (define-any->vector . tags)
+  `(begin
+     ,@(map (lambda (tag)
+              `(define (,(symbol-append 'any-> tag 'vector) obj)
+                 (cond ((,(symbol-append tag 'vector?) obj) obj)
+                       ((pair? obj) (,(symbol-append 'list-> tag 'vector) obj))
+                       ((generalized-vector? obj)
+                        (let* ((len (generalized-vector-length obj))
+                               (v (,(symbol-append 'make- tag 'vector) len)))
+                          (let lp ((i 0))
+                            (if (< i len)
+                                (begin
+                                  (,(symbol-append tag 'vector-set!)
+                                   v i (generalized-vector-ref obj i))
+                                  (lp (1+ i)))
+                                v))))
+                       (else (scm-error 'wrong-type-arg #f "" '() (list obj))))))
+            tags)))
+
+(define-any->vector u8 s8 u16 s16 u32 s32 u64 s64 f32 f64 c32 c64)