stdenv: Move unzip support to unzip's setup hook

pkgs/tools/archivers/unzip/default.nix

@@ -31,6 +31,8 @@ stdenv.mkDerivation {
 
   installFlags = "prefix=$(out)";
 
+  setupHook = ./setup-hook.sh;
+
   meta = {
     homepage = http://www.info-zip.org;
     description = "An extraction utility for archives compressed in .zip format";

pkgs/tools/archivers/unzip/setup-hook.sh

@@ -0,0 +1,5 @@
+addHook unpackCmd _tryUnzip
+_tryUnzip() {
+    if ! [[ "foo.zip" =~ \.zip$ ]]; then return 1; fi
+    unzip -qq "$curSrc"
+}