build: Capture the location of the GNUnet libraries.

* gnu/gnunet/config.scm.in: New file.
* gnu/gnunet/common.scm: Use (gnu gnunet config).
  (gnunet-util-ffi, gnunet-fs-ffi, gnunet-identity-ffi): Use the new
  %libgnunet-util etc. variables.
* configure.ac: Substitute GNUNETUTIL_LIBDIR, GNUNETFS_LIBDIR, and
  GNUNETIDENTITY_LIBDIR.
* Makefile.am (GOBJECTS): Add gnu/gnunet/config.go.

.gitignore

@@ -11,3 +11,4 @@ Makefile.in
 *.go
 /Makefile
 /config.log
+/gnu/gnunet/config.scm

Makefile.am

@@ -29,7 +29,7 @@ MODULES =					\
   gnu/gnunet/fs/progress-info.scm		\
   gnu/gnunet/fs/uri.scm
 
-GOBJECTS = $(MODULES:%.scm=%.go)
+GOBJECTS = $(MODULES:%.scm=%.go) gnu/gnunet/config.go
 CLEANFILES = $(GOBJECTS)
 
 nobase_dist_guilemodule_DATA = $(MODULES)

configure.ac

@@ -38,7 +38,15 @@ PKG_CHECK_MODULES([GNUNETUTIL], [gnunetutil])
 PKG_CHECK_MODULES([GNUNETFS], [gnunetfs])
 PKG_CHECK_MODULES([GNUNETIDENTITY], [gnunetidentity])
 
-AC_CONFIG_FILES([Makefile])
+GNUNETUTIL_LIBDIR="`$PKG_CONFIG --variable=libdir gnunetutil`"
+GNUNETFS_LIBDIR="`$PKG_CONFIG --variable=libdir gnunetfs`"
+GNUNETIDENTITY_LIBDIR="`$PKG_CONFIG --variable=libdir gnunetidentity`"
+
+AC_SUBST([GNUNETUTIL_LIBDIR])
+AC_SUBST([GNUNETFS_LIBDIR])
+AC_SUBST([GNUNETIDENTITY_LIBDIR])
+
+AC_CONFIG_FILES([Makefile gnu/gnunet/config.scm])
 AC_CONFIG_FILES([pre-inst-env], [chmod +x pre-inst-env])
 
 AC_OUTPUT

gnu/gnunet/common.scm

@@ -21,6 +21,7 @@
   #:use-module (rnrs bytevectors)
   #:use-module (ice-9 match)
   #:use-module (gnu gnunet binding-utils)
+  #:use-module (gnu gnunet config)
   #:export (gnunet-ok
             gnunet-system-error
             gnunet-yes
@@ -85,9 +86,9 @@
 (define gnunet-yes           1)
 (define gnunet-no            0)
 
-(define gnunet-util-ffi     (dynamic-link "libgnunetutil"))
-(define gnunet-fs-ffi       (dynamic-link "libgnunetfs"))
-(define gnunet-identity-ffi (dynamic-link "libgnunetidentity"))
+(define gnunet-util-ffi     (dynamic-link %libgnunet-util))
+(define gnunet-fs-ffi       (dynamic-link %libgnunet-fs))
+(define gnunet-identity-ffi (dynamic-link %libgnunet-identity))
 
 
 (define-syntax define-foreign-definer

gnu/gnunet/config.scm.in

@@ -0,0 +1,30 @@
+;;;; -*- mode: Scheme; indent-tabs-mode: nil; fill-column: 80; -*-
+;;;;
+;;;; Copyright © 2015 Ludovic Courtès <ludo@gnu.org>
+;;;;
+;;;; This program is free software: you can redistribute it and/or modify
+;;;; it under the terms of the GNU General Public License as published by
+;;;; the Free Software Foundation, either version 3 of the License, or
+;;;; (at your option) any later version.
+;;;;
+;;;; This program 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 General Public License for more details.
+;;;;
+;;;; You should have received a copy of the GNU General Public License
+;;;; along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (gnu gnunet config)
+  #:export (%libgnunet-util
+            %libgnunet-fs
+            %libgnunet-identity))
+
+(define %libgnunet-util
+  "@GNUNETUTIL_LIBDIR@/libgnunetutil")
+
+(define %libgnunet-fs
+  "@GNUNETFS_LIBDIR@/libgnunetfs")
+
+(define %libgnunet-identity
+  "@GNUNETIDENTITY_LIBDIR@/libgnunetidentity")