maint: Add Guix build files.

* guix.scm, build-aux/manifest.scm: New files.
* Makefile.am (EXTRA_DIST): Add them.
* README: Mention it.

Makefile.am

@@ -81,7 +81,8 @@ EXTRA_DIST = LICENSE HACKING GUILE-VERSION			\
 	     gnulib-local/m4/clock_time.m4.diff			\
 	     gnulib-local/build-aux/git-version-gen.diff	\
 	     libguile/texi-fragments-to-docstrings		\
-	     gdbinit
+	     gdbinit						\
+	     guix.scm build-aux/manifest.scm
 
 TESTS = check-guile
 TESTS_ENVIRONMENT = @LOCALCHARSET_TESTS_ENVIRONMENT@

README

@@ -128,6 +128,16 @@ When building from a Git checkout, these additional packages are needed:
   - GNU Texinfo
   - GNU Gperf
 
+If you use GNU Guix, you can obtain a shell for development with all the
+dependencies by running the following command from the top directory of
+the checkout:
+
+  guix shell
+
+You can also build Guile by running:
+
+  guix build -f guix.scm
+
 
 Special Instructions For Some Systems =====================================
 

build-aux/manifest.scm

@@ -0,0 +1,61 @@
+;;; Copyright © 2023 Free Software Foundation, Inc.
+;;;
+;;; This file is part of GNU Guile.
+;;;
+;;; GNU Guile 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.
+;;;
+;;; GNU Guile 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 GNU Guile.  If not, see <http://www.gnu.org/licenses/>.
+
+;; This file defines a Guix manifest for use by Cuirass, the continuous
+;; integration service running at <https://ci.guix.gnu.org>.
+
+(use-modules (guix)
+             (guix profiles))
+
+(define guile
+  (load "../guix.scm"))
+
+(define* (package->manifest-entry* package system
+                                   #:key target)
+  "Return a manifest entry for PACKAGE on SYSTEM, optionally cross-compiled to
+TARGET."
+  (manifest-entry
+    (inherit (package->manifest-entry package))
+    (name (string-append (package-name package) "." system
+                         (if target
+                             (string-append "." target)
+                             "'")))
+    (item (with-parameters ((%current-system system)
+                            (%current-target-system target))
+            package))))
+
+(define native-builds
+  (manifest
+   (map (lambda (system)
+          (package->manifest-entry* guile system))
+        '("x86_64-linux" "i686-linux"
+          "aarch64-linux" "armhf-linux"
+          "powerpc64le-linux"))))
+
+(define cross-builds
+  (manifest
+   (map (lambda (target)
+          (package->manifest-entry* guile "x86_64-linux"
+                                    #:target target))
+        '("i586-pc-gnu"
+          ;; "arm-linux-gnueabihf"
+          "aarch64-linux-gnu"
+          "riscv64-linux-gnu"
+          "i686-w64-mingw32"
+          "x86_64-linux-gnu"))))
+
+(concatenate-manifests (list native-builds cross-builds))

guix.scm

@@ -0,0 +1,143 @@
+;;; Copyright © 2023 Free Software Foundation, Inc.
+;;;
+;;; This file is part of GNU Guile.
+;;;
+;;; GNU Guile 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.
+;;;
+;;; GNU Guile 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 GNU Guile.  If not, see <http://www.gnu.org/licenses/>.
+
+;; This file defines a Guix package.  It can be used to spawn an
+;; interactive development environment:
+;;
+;;   guix shell
+;;
+;; Or it can be used to build Guile from a checkout in an isolated
+;; environment:
+;;
+;;   guix build -f guix.scm
+;;
+;; Likewise, you may cross-compile it:
+;;
+;;   guix build -f guix.scm --target=x86_64-w64-mingw32
+;;
+;; … or perform a native build for another architecture, assuming
+;; either offloading or transparent QEMU emulation is set up:
+;;
+;;   guix build -f guix.scm -s riscv64-linux
+
+(use-modules (guix)
+             (guix git-download)
+             (guix build-system gnu)
+             ((guix licenses) #:prefix license:)
+             (gnu packages)
+             (gnu packages pkg-config))
+
+(let ((vcs-file? (or (git-predicate (current-source-directory))
+                     (const #t)))
+      (S specification->package))
+  (package
+    (name "guile")
+    (version "3.0.000-git")
+    (source (local-file "." "guile-checkout"
+                        #:recursive? #t
+                        #:select? vcs-file?))
+    (build-system gnu-build-system)
+    (arguments
+     (list #:configure-flags
+           #~'("--enable-mini-gmp"
+               #$@(if (target-x86-32?) ;<https://issues.guix.gnu.org/49368>
+                      '("--disable-static" "CFLAGS=-g -O2 -fexcess-precision=standard")
+                      '("--disable-static")))     ;saves 3 MiB
+
+           #:phases
+           #~(modify-phases %standard-phases
+               (add-before 'bootstrap 'set-version
+                 (lambda _
+                   ;; Tell 'git-version-gen' what version this is, or it will
+                   ;; just pick "UNKNOWN", making it unusable as a replacement
+                   ;; for 'guile-3.0'.  XXX: This is inaccurate when using
+                   ;; '--with-branch' but using (package-version this-package)
+                   ;; wouldn't give us a valid version string.
+                   (call-with-output-file ".tarball-version"
+                     (lambda (port)
+                       (display #$version port)))
+
+                   ;; Set this one as well so 'version.test' passes.
+                   (substitute* "GUILE-VERSION"
+                     (("^GUILE_MICRO_VERSION=.*")
+                      "GUILE_MICRO_VERSION=99\n"))))
+               (add-before 'configure 'pre-configure
+                 (lambda* (#:key inputs #:allow-other-keys)
+                   ;; Tell (ice-9 popen) the file name of Bash.
+                   (let ((bash (false-if-exception
+                                (search-input-file inputs "/bin/sh"))))
+                     (substitute* "module/ice-9/popen.scm"
+                       ;; If bash is #f allow fallback for user to provide
+                       ;; "bash" in PATH.  This happens when cross-building to
+                       ;; MinGW for which we do not have Bash yet.
+                       (("/bin/sh")
+                        (or bash "/bin/sh")))))))))
+
+    (native-inputs
+     (append (map S '("autoconf"
+                      "automake"
+                      "libtool"
+                      "gettext"
+                      "flex"
+                      "texinfo"
+                      "texlive-base"              ;for "make pdf"
+                      "texlive-epsf"
+                      "gperf"
+                      "git"
+                      "gdb"
+                      "strace"
+                      "readline"
+                      "lzip"))
+
+             ;; Ensure we get a cross-pkg-config when needed.
+             (list pkg-config)
+
+             ;; When cross-compiling, a native version of Guile itself
+             ;; is needed.
+             (if (%current-target-system)
+                 (list this-package)
+                 '())))
+    (inputs
+     (append (list (S "libffi"))
+
+             ;; We need Bash when cross-compiling because some of the
+             ;; scripts in bin/ refer to it.  Use 'bash-minimal' because
+             ;; we don't need an interactive Bash with Readline and all.
+             (if (target-mingw?)
+                 (list (S "libiconv"))
+                 (list (S "bash-minimal")))))
+    (propagated-inputs
+     (map S '("libunistring" "libgc")))
+
+    (outputs '("out" "debug"))
+
+    (native-search-paths
+     (list (search-path-specification
+            (variable "GUILE_LOAD_PATH")
+            (files '("share/guile/site/3.0")))
+           (search-path-specification
+            (variable "GUILE_LOAD_COMPILED_PATH")
+            (files '("lib/guile/3.0/site-ccache")))))
+    (synopsis "Scheme implementation intended especially for extensions")
+    (description
+     "Guile is the GNU Ubiquitous Intelligent Language for Extensions, the
+official extension language of the GNU system.  It is an implementation of
+the Scheme language which can be easily embedded in other applications to
+provide a convenient means of extending the functionality of the application
+without requiring the source code to be rewritten.")
+    (home-page "https://www.gnu.org/software/guile/")
+    (license license:lgpl3+)))