gnu: xlockmore: Improve package style.

* gnu/packages/xdisorg.scm (xlockmore)[arguments]: Use G-expressions.
[inputs]: Remove labels.

gnu/packages/xdisorg.scm

@@ -1014,15 +1014,14 @@ shows it again when the mouse cursor moves or a mouse button is pressed.")
                 "0vndfwccnvkaaraprjam8pmx0aj55va0ag64q6snxw83nbf1ywrh"))))
     (build-system gnu-build-system)
     (arguments
-     '(#:configure-flags (list (string-append "--enable-appdefaultdir="
-                                              (assoc-ref %outputs "out")
+     (list
+      #:configure-flags
+      #~(list (string-append "--enable-appdefaultdir="
+                             #$output
                              "/lib/X11/app-defaults"))
       #:tests? #f))                     ;no such thing as a test suite
     (inputs
-     `(("libX11" ,libx11)
-       ("libXext" ,libxext)
-       ("libXt" ,libxt)
-       ("linux-pam" ,linux-pam)))
+     (list libx11 libxext libxt linux-pam))
     (home-page "https://sillycycle.com/xlockmore.html")
     (synopsis "Screen locker for the X Window System")
     (description