gnu: xrandr-invert-colors: Fix executable name.

* gnu/packages/xdisorg.scm (xrandr-invert-colors)[arguments]: Remove
‘.bin’ suffix from the binary during the 'install phase, and don't
return #t.

gnu/packages/xdisorg.scm

@@ -2226,11 +2226,14 @@ to automatically turn it on on login.")
        (modify-phases %standard-phases
          (delete 'configure)
          (replace 'install
+           ;; It's simpler to install the single binary ourselves than to patch
+           ;; the Makefile's install target into working.
            (lambda* (#:key outputs #:allow-other-keys)
              (let* ((out  (assoc-ref outputs "out"))
                     (bin  (string-append out "/bin")))
-               (install-file "xrandr-invert-colors.bin" bin)
-               #t))))))
+               (mkdir-p bin)
+               (copy-file "xrandr-invert-colors.bin"
+                          (string-append bin "/xrandr-invert-colors"))))))))
     (inputs
      `(("libxrandr" ,libxrandr)))
     (home-page "https://github.com/zoltanp/xrandr-invert-colors")