gnu: bzip2: Use 'modify-phases' syntax.

* gnu/packages/compression.scm (bzip2)[arguments]: Use 'modify-phases' syntax.

Signed-off-by: Marius Bakke <mbakke@fastmail.com>

gnu/packages/compression.scm

@@ -207,34 +207,6 @@ file; as a result, it is often used in conjunction with \"tar\", resulting in
    (home-page "https://www.gnu.org/software/gzip/")))
 
 (define-public bzip2
-  (let ((build-shared-lib
-         ;; Build a shared library.
-         '(lambda* (#:key inputs #:allow-other-keys)
-            (patch-makefile-SHELL "Makefile-libbz2_so")
-            (zero? (system* "make" "-f" "Makefile-libbz2_so"))))
-        (install-shared-lib
-         '(lambda* (#:key outputs #:allow-other-keys)
-            (let* ((out    (assoc-ref outputs "out"))
-                   (libdir (string-append out "/lib")))
-              (for-each (lambda (file)
-                          (let ((base (basename file)))
-                            (format #t "installing `~a' to `~a'~%"
-                                    base libdir)
-                            (copy-file file
-                                       (string-append libdir "/" base))))
-                        (find-files "." "^libbz2\\.so")))))
-        (set-cross-environment
-         '(lambda* (#:key target #:allow-other-keys)
-            (substitute* (find-files "." "Makefile")
-              (("CC=.*$")
-               (string-append "CC = " target "-gcc\n"))
-              (("AR=.*$")
-               (string-append "AR = " target "-ar\n"))
-              (("RANLIB=.*$")
-               (string-append "RANLIB = " target "-ranlib\n"))
-              (("^all:(.*)test" _ prerequisites)
-               ;; Remove 'all' -> 'test' dependency.
-               (string-append "all:" prerequisites "\n"))))))
   (package
     (name "bzip2")
     (version "1.0.6")
@@ -251,22 +223,38 @@ file; as a result, it is often used in conjunction with \"tar\", resulting in
                   (guix build utils)
                   (srfi srfi-1))
        #:phases
-         ,(if (%current-target-system)
+       (modify-phases %standard-phases
-
+         (replace 'configure
+           (lambda* (#:key target #:allow-other-keys)
+             (if ,(%current-target-system)
                  ;; Cross-compilation: use the cross tools.
-              `(alist-cons-before
+                 (substitute* (find-files "." "Makefile")
-                'build 'build-shared-lib ,build-shared-lib
+                   (("CC=.*$")
-                (alist-cons-after
+                    (string-append "CC = " target "-gcc\n"))
-                 'install 'install-shared-lib ,install-shared-lib
+                   (("AR=.*$")
-                 (alist-replace 'configure ,set-cross-environment
+                    (string-append "AR = " target "-ar\n"))
-                                %standard-phases)))
+                   (("RANLIB=.*$")
-
+                    (string-append "RANLIB = " target "-ranlib\n"))
-              ;; Native compilation: build the shared library.
+                   (("^all:(.*)test" _ prerequisites)
-              `(alist-cons-before
+                    ;; Remove 'all' -> 'test' dependency.
-                'build 'build-shared-lib ,build-shared-lib
+                    (string-append "all:" prerequisites "\n")))
-                (alist-cons-after
+                 #t)))
-                 'install 'install-shared-lib ,install-shared-lib
+         (add-before 'build 'build-shared-lib
-                 (alist-delete 'configure %standard-phases))))
+           (lambda* (#:key inputs #:allow-other-keys)
+             (patch-makefile-SHELL "Makefile-libbz2_so")
+             (zero? (system* "make" "-f" "Makefile-libbz2_so"))))
+         (add-after 'install 'install-shared-lib
+           (lambda* (#:key outputs #:allow-other-keys)
+             (let* ((out    (assoc-ref outputs "out"))
+                    (libdir (string-append out "/lib")))
+               (for-each (lambda (file)
+                           (let ((base (basename file)))
+                             (format #t "installing `~a' to `~a'~%"
+                                     base libdir)
+                             (copy-file file
+                                        (string-append libdir "/" base))))
+                         (find-files "." "^libbz2\\.so")))
+             #t)))
 
        #:make-flags (list (string-append "PREFIX="
                                          (assoc-ref %outputs "out")))
@@ -284,7 +272,7 @@ being around twice as fast at compression and six times faster at
 decompression.")
     (license (license:non-copyleft "file://LICENSE"
                                    "See LICENSE in the distribution."))
-      (home-page "http://www.bzip.org/"))))
+    (home-page "http://www.bzip.org/")))
 
 (define-public lbzip2
   (package