sct: backport #17163

pkgs/tools/X11/sct/default.nix

···
   buildInputs = [libX11 libXrandr];
   src = fetchurl {
     url = http://www.tedunangst.com/flak/files/sct.c;
-    sha256 = "1bivy0sl5v1jsq4jbq6p9hplz6cvw4nx9rc96p2kxsg506rqllc5";
+    sha256 = "01f3ndx3s6d2qh2xmbpmhd4962dyh8yp95l87xwrs4plqdz6knhd";
+
+     # Discussion regarding the checksum and the source code can be found in issue #17163
+     # The code seems unmaintained, yet an unknown (probably small change) in the code caused
+     # failed builds as the checksum had changed.
+     # The checksum is updated for now, however, this is unpractical and potentially unsafe
+     # so any future changes might warrant a fork of the (feature complete) project.
+     # The code is under public domain.
   };
   phases = ["patchPhase" "buildPhase" "installPhase"];
   patchPhase = ''