gnu: mpv: Use G-expressions.

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

gnu/packages/video.scm

@@ -2169,9 +2169,10 @@ (define-public mpv
                (base32 "12qxwm1ww5vhjddl8yvj1xa0n1fi9z3lmzwhaiday2v59ca0qgsk"))))
     (build-system waf-build-system)
     (arguments
-     '(#:phases
-       (modify-phases %standard-phases
-         (add-after 'unpack 'patch-paths
+     (list
+      #:phases
+      #~(modify-phases %standard-phases
+          (add-after 'unpack 'patch-file-names
             (lambda* (#:key inputs #:allow-other-keys)
               (substitute* "player/lua/ytdl_hook.lua"
 		(("\"yt-dlp\",")
@@ -2186,9 +2187,10 @@ (define-public mpv
               (setenv "PYTHONHASHSEED" "1")))
           (add-before 'configure 'set-up-waf
             (lambda* (#:key inputs #:allow-other-keys)
-             (copy-file (search-input-file inputs "/bin/waf") "waf")
+              (copy-file (search-input-file inputs "bin/waf") "waf")
               (setenv "CC" "gcc"))))
-       #:configure-flags (list "--enable-libmpv-shared"
+      #:configure-flags
+      #~(list "--enable-libmpv-shared"
               "--enable-cdda"
               "--enable-dvdnav"
               "--disable-build-date")