libsForQt5.kconfig: unsplit bin output

This breaks with the new wrapping and executables in libexec.

pkgs/development/libraries/kde-frameworks/kconfig.nix

@@ -7,6 +7,7 @@
 
 mkDerivation {
   pname = "kconfig";
+  outputs = [ "out" "dev" ];
   nativeBuildInputs = [ extra-cmake-modules ];
   buildInputs = [ qttools ];
   propagatedBuildInputs = [ qtbase ];