gnu: gmime: Use G-expressions.

* gnu/packages/mail.scm (gmime)[arguments]:
Rewrite as G-expressions.

gnu/packages/mail.scm

@@ -771,25 +771,13 @@ It adds a large amount of new and improved features to mutt.")
        (sha256
         (base32 "0yiylbw9iy49hgj29czinv246hh5c18qv6qkvbdrmq9z5m00sp01"))))
     (build-system gnu-build-system)
-    (native-inputs
-     (list autoconf
-           automake
-           pkg-config
-           gnupg                        ; for tests only
-           gobject-introspection
-           gtk-doc
-           libtool
-           vala
-           which))                      ; to find libtool, &c.
-    (inputs (list glib gpgme zlib))
     (arguments
-     `(#:configure-flags
+     (list #:configure-flags
-         (list "--enable-gtk-doc=yes"
+           #~(list "--enable-gtk-doc=yes"
                    "--enable-introspection=yes")
            #:phases
-       (modify-phases %standard-phases
+           #~(modify-phases %standard-phases
-         (add-after
+               (add-after 'unpack 'patch-paths-in-tests
-          'unpack 'patch-paths-in-tests
                  (lambda _
                    ;; The test programs run several programs using 'system' with
                    ;; hard-coded paths.  Here we patch them all.
@@ -801,7 +789,19 @@ It adds a large amount of new and improved features to mutt.")
                         (let* ((base (basename prog-path))
                                (prog (which base)))
                           (string-append pre
-                                  (or prog (error "not found: " base))))))))))))
+                                         (or prog (error "not found: "
+                                                         base))))))))))))
+    (native-inputs
+     (list autoconf
+           automake
+           pkg-config
+           gnupg                        ; for tests only
+           gobject-introspection
+           gtk-doc
+           libtool
+           vala
+           which))                      ; to find libtool, &c.
+    (inputs (list glib gpgme zlib))
     (home-page "http://spruce.sourceforge.net/gmime/")
     (synopsis "MIME message parser and creator library")
     (description