treewide: use less phases if not necessary

This removes some skipping of e.g. fixupPhase and cleans up occurences
where this led to duplicating code

pkgs/tools/networking/ratools/default.nix

@@ -11,15 +11,11 @@ stdenv.mkDerivation rec {
     sha256 = "07m45bn9lzgbfihmxic23wqp73nxg5ihrvkigr450jq6gzvgwawq";
   };
 
-  phases = [ "unpackPhase" "buildPhase" "installPhase" ];
-
   makeFlags = "-C src";
 
   installPhase = ''
-    mkdir -p $out/{bin,sbin,share/man/man8}
-    cp bin/ractl $out/bin
-    cp bin/rad $out/sbin
-    cp man/* $out/share/man/man8
+    install -vD bin/* -t $out/bin
+    install -vD man/* -t $out/share/man/man8
   '';
 
   meta = with stdenv.lib; {