iproute: don't use host BASH for scripts, fix for cross

Doesn't eliminate glibc dep, somehow
a dependency on host's "db" leaks,
but it's a start.

Also don't attempt to build unused 'netem' tools,
avoiding need to use HOSTCC.

pkgs/os-specific/linux/iproute/default.nix

@@ -12,6 +12,8 @@ stdenv.mkDerivation rec {
   preConfigure = ''
     patchShebangs ./configure
     sed -e '/ARPDDIR/d' -i Makefile
+    # Don't build netem tools--they're not installed and require HOSTCC
+    substituteInPlace Makefile --replace " netem " " "
   '';
 
   makeFlags = [
@@ -37,6 +39,10 @@ stdenv.mkDerivation rec {
 
   enableParallelBuilding = true;
 
+  postInstall = ''
+    PATH=${stdenv.shell}/bin:$PATH patchShebangs $out/sbin
+  '';
+
   meta = with stdenv.lib; {
     homepage = https://wiki.linuxfoundation.org/networking/iproute2;
     description = "A collection of utilities for controlling TCP/IP networking and traffic control in Linux";