gnu: busybox: Use 'modify-phases'.

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

gnu/packages/busybox.scm

@@ -42,11 +42,10 @@
     (build-system gnu-build-system)
     (arguments
      `(#:phases
-       (alist-replace
-        'configure
-        (lambda _ (zero? (system* "make" "defconfig")))
-        (alist-replace
-         'check
+       (modify-phases %standard-phases
+         (replace 'configure
+           (lambda _ (zero? (system* "make" "defconfig"))))
+         (replace 'check
            (lambda _
            (substitute* '("testsuite/du/du-s-works"
                            "testsuite/du/du-works")
@@ -84,16 +83,14 @@
                            ;; "V=1"
                            "SKIP_KNOWN_BUGS=1"
                            "SKIP_INTERNET_TESTS=1"
-                           "check")))
-         (alist-replace
-          'install
+                           "check"))))
+         (replace 'install
            (lambda* (#:key outputs #:allow-other-keys)
              (let ((out (assoc-ref outputs "out")))
                (zero?
                 (system* "make"
                          (string-append "CONFIG_PREFIX=" out)
-                        "install"))))
-          %standard-phases)))))
+                         "install"))))))))
     (native-inputs `(("perl" ,perl) ; needed to generate the man pages (pod2man)
                      ;; The following are needed by the tests.
                      ("inetutils" ,inetutils)