gnu: glib: Use modify-phases syntax.

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

gnu/packages/glib.scm

@@ -160,8 +160,9 @@ shared NFS home directories.")
       ("perl" ,perl)                              ; needed by GIO tests
       ("bash" ,bash)))
    (arguments
-    '(#:phases (alist-cons-before
-                'build 'pre-build
+    '(#:phases
+      (modify-phases %standard-phases
+        (add-before 'build 'pre-build
           (lambda* (#:key inputs outputs #:allow-other-keys)
             ;; For tests/gdatetime.c.
             (setenv "TZDIR"
@@ -181,8 +182,7 @@ shared NFS home directories.")
             (substitute* "gio/tests/gdbus-serialization.c"
               (("g_test_add_func \
 \\(\"/gdbus/message-serialize/double-array\", test_double_array\\);" all)
-                     (string-append "/* " all " */"))))
-                %standard-phases)
+               (string-append "/* " all " */"))))))
 
       ;; Note: `--docdir' and `--htmldir' are not honored, so work around it.
       #:configure-flags (list (string-append "--with-html-dir="