diff --git a/pkgs/applications/virtualization/qemu/default.nix b/pkgs/applications/virtualization/qemu/default.nix
index d09926da7cd..8277261a150 100644
--- a/pkgs/applications/virtualization/qemu/default.nix
+++ b/pkgs/applications/virtualization/qemu/default.nix
@@ -59,6 +59,10 @@ stdenv.mkDerivation rec {
 
   hardeningDisable = [ "stackprotector" ];
 
+  preConfigure = ''
+    unset CPP # intereferes with dependency calculation
+  '';
+
   configureFlags =
     [ "--smbd=smbd" # use `smbd' from $PATH
       "--audio-drv-list=${audio}"