gnu: perl: Use 'modify-phases'.

* gnu/packages/perl.scm (perl)[arguments]: Use 'modify-phases' instead of
  'alist-replace'.

gnu/packages/perl.scm

@@ -51,7 +51,8 @@
     (arguments
      '(#:tests? #f
        #:phases
-       (alist-replace
+       (modify-phases %standard-phases
+         (replace
           'configure
           (lambda* (#:key inputs outputs #:allow-other-keys)
             (let ((out  (assoc-ref outputs "out"))
@@ -71,8 +72,7 @@
                         "-Dinstallstyle=lib/perl5"
                         "-Duseshrplib"
                         (string-append "-Dlocincpth=" libc "/include")
-                      (string-append "-Dloclibpth=" libc "/lib")))))
-        %standard-phases)))
+                        (string-append "-Dloclibpth=" libc "/lib")))))))))
     (native-search-paths (list (search-path-specification
                                 (variable "PERL5LIB")
                                 (files '("lib/perl5/site_perl")))))