qemu-kvm: Remove

But install a qemu-kvm wrapper in qemu.

pkgs/applications/virtualization/qemu/default.nix

@@ -1,5 +1,6 @@
 { stdenv, fetchurl, python, zlib, pkgconfig, glib, ncurses, perl, pixman
 , attr, libcap, vde2, alsaLib, texinfo, libuuid
+, makeWrapper
 , sdlSupport ? true, SDL
 , vncSupport ? true, libjpeg, libpng
 , spiceSupport ? true, spice, spice_protocol
@@ -16,7 +17,7 @@ stdenv.mkDerivation rec {
 
   buildInputs =
     [ python zlib pkgconfig glib ncurses perl pixman attr libcap
-      vde2 alsaLib texinfo libuuid
+      vde2 alsaLib texinfo libuuid makeWrapper
     ]
     ++ stdenv.lib.optionals sdlSupport [ SDL ]
     ++ stdenv.lib.optionals vncSupport [ libjpeg libpng ]
@@ -31,6 +32,15 @@ stdenv.mkDerivation rec {
     ++ stdenv.lib.optional spiceSupport "--enable-spice"
     ++ stdenv.lib.optional x86Only "--target-list=i386-softmmu,x86_64-softmmu";
 
+  postInstall =
+    ''
+      # Add a ‘qemu-kvm’ wrapper for compatibility/convenience.
+      p="$out/bin/qemu-system-${if stdenv.system == "x86_64-linux" then "x86_64" else "i386"}"
+      if [ -e "$p" ]; then
+        makeWrapper "$p" $out/bin/qemu-kvm --add-flags "-enable-kvm"
+      fi
+    '';
+
   meta = {
     homepage = http://www.qemu.org/;
     description = "A generic and open source machine emulator and virtualizer";