gnu: httpfs2: Use G-expressions.

* gnu/packages/file-systems.scm (httpfs2)[arguments]:
Rewrite as G-expressions.

gnu/packages/file-systems.scm

@@ -586,15 +586,14 @@ Extensible File Allocation Table} file systems.  Included are
     (inputs
      (list fuse gnutls))
     (arguments
-     `(#:phases
-       (modify-phases %standard-phases
+     (list #:phases
+           #~(modify-phases %standard-phases
                (delete 'configure)      ; no configure script
                (replace 'install
                  ;; There's no ‘install’ target. Install all variants manually.
-           (lambda* (#:key outputs #:allow-other-keys)
-             (let* ((out (assoc-ref outputs "out"))
-                    (bin (string-append out "/bin"))
-                    (man1 (string-append out "/share/man/man1")))
+                 (lambda _
+                   (let* ((bin (string-append #$output "/bin"))
+                          (man1 (string-append #$output "/share/man/man1")))
                      (mkdir-p bin)
                      (mkdir-p man1)
                      (for-each
@@ -605,9 +604,9 @@ Extensible File Allocation Table} file systems.  Included are
                       (list "httpfs2"
                             "httpfs2-mt"
                             "httpfs2-ssl"
-                      "httpfs2-ssl-mt")))
-             #t)))
-       #:make-flags (list "CC=gcc")
+                            "httpfs2-ssl-mt"))))))
+           #:make-flags
+           #~(list "CC=gcc")
            #:parallel-build? #f         ; can result in missing man pages
            #:tests? #f))                ; no tests
     (home-page "https://sourceforge.net/projects/httpfs/")