gnu: git: Use 'modify-phases'.

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

gnu/packages/version-control.scm

@@ -166,15 +166,14 @@ (define-public git
       #:modules ((srfi srfi-1)
                  ,@%gnu-build-system-modules)
       #:phases
-       (alist-cons-after
-        'configure 'patch-makefile-shebangs
+      (modify-phases %standard-phases
+        (add-after 'configure 'patch-makefile-shebangs
           (lambda _
             (substitute* "Makefile"
               (("/bin/sh") (which "sh"))
               (("/usr/bin/perl") (which "perl"))
-            (("/usr/bin/python") (which "python"))))
-        (alist-cons-after
-         'install 'install-shell-completion
+              (("/usr/bin/python") (which "python")))))
+        (add-after 'install 'install-shell-completion
           (lambda* (#:key outputs #:allow-other-keys)
             (let* ((out         (assoc-ref outputs "out"))
                    (completions (string-append out "/etc/bash_completion.d")))
@@ -182,9 +181,8 @@ (define-public git
               (mkdir-p completions)
               (copy-file "contrib/completion/git-completion.bash"
                          (string-append completions "/git"))
-             #t))
-         (alist-cons-after
-          'install 'split
+              #t)))
+        (add-after 'install 'split
           (lambda* (#:key inputs outputs #:allow-other-keys)
             ;; Split the binaries to the various outputs.
             (let* ((out      (assoc-ref outputs "out"))
@@ -256,8 +254,7 @@ (define-public git
               ;; specify a single directory, not a search path.
               (wrap-program (string-append out "/bin/git")
                 `("PATH" ":" prefix
-                  ("$HOME/.guix-profile/libexec/git-core")))))
-          %standard-phases)))))
+                  ("$HOME/.guix-profile/libexec/git-core")))))))))
 
    (native-search-paths
     ;; For HTTPS access, Git needs a single-file certificate bundle, specified