gnu: Add qtcolorwidgets.

* gnu/packages/qt.scm (qtcolorwidgets): New variable.

Signed-off-by: Ricardo Wurmus <rekado@elephly.net>

gnu/packages/qt.scm

@@ -2232,3 +2232,33 @@ a binding language:
 @item Creating from Singleton QML QObject defined in the binded language
 @end itemize\n")
     (license license:lgpl3)))                    ;version 3 only (+ exception)
+
+;; There have been no public releases yet.
+(define-public qtcolorwidgets
+  (let ((commit "a95f72e935fe9e046061a1d1c3930cbfbcb533e0")
+        (revision "1"))
+    (package
+      (name "qtcolorwidgets")
+      (version (git-version "0" revision commit))
+      (source (origin
+                (method git-fetch)
+                (uri (git-reference
+                      (url "https://gitlab.com/mattia.basaglia/Qt-Color-Widgets")
+                      (commit commit)))
+                (file-name (git-file-name name version))
+                (sha256
+                 (base32
+                  "0dkiwlqh2gwhlp78c1fmchj3shl4p9inspcl96ya5aa8mn6kydy8"))))
+      (build-system cmake-build-system)
+      (arguments `(#:tests? #f)) ; There are no tests
+      (native-inputs
+       `(("qttools" ,qttools)))
+      (inputs
+       `(("qtbase" ,qtbase)))
+      (home-page "https://gitlab.com/mattia.basaglia/Qt-Color-Widgets")
+      (synopsis "Color management widgets")
+      (description "QtColorWidgets provides a Qt color dialog that is more
+user-friendly than the default @code{QColorDialog} and several other
+color-related widgets.")
+      ;; Includes a license exception for combining with GPL2 code.
+      (license license:lgpl3+))))