rPackages.littler: fix build (#51282)

littler gives a wrapped called `r` (or `lr` for non-case-preserving
systems like Darwin) which works as shebang or pipe target.

The build was completely broken before (missing deps).

Symlink executables and manpage into standard locations so that this
packages also works in `environment.systemPackages`.

pkgs/development/r-modules/default.nix

@@ -950,6 +950,18 @@ let
       preConfigure = "patchShebangs configure";
     });
 
+    littler = old.littler.overrideAttrs (attrs: with pkgs; {
+      buildInputs = [ pcre lzma zlib bzip2 icu which ] ++ attrs.buildInputs;
+      postInstall = ''
+        install -d $out/bin $out/share/man/man1
+        ln -s ../library/littler/bin/r $out/bin/r
+        ln -s ../library/littler/bin/r $out/bin/lr
+        ln -s ../../../library/littler/man-page/r.1 $out/share/man/man1
+        # these won't run without special provisions, so better remove them
+        rm -r $out/library/littler/script-tests
+      '';
+    });
+
   };
 in
   self