quickemu: fix Samba shares

This makes it possible to share your home dir with a Windows guest.

* use `qemu_full` for the correct smbd path; the fallback path `/usr/sbin/smbd` fails on NixOS [1]
* make the `smbd` binary available to quickemu, enabling it to start qemu with Samba support [2]

[1] https://github.com/qemu/qemu/blob/28b8a57ad63670aa0ce90334523dc552b13b4336/meson.build#L2217
[2] https://github.com/quickemu-project/quickemu/blob/626591bca87e47c545d8fff9a9be0be24f26c3d8/quickemu#L1083

pkgs/by-name/qu/quickemu/package.nix

@@ -14,7 +14,7 @@
   pciutils,
   procps,
   python3,
-  qemu,
+  qemu_full,
   socat,
   spice-gtk,
   swtpm,
@@ -42,7 +42,7 @@ let
     pciutils
     procps
     python3
-    qemu
+    qemu_full
     socat
     swtpm
     util-linux
@@ -73,6 +73,7 @@ stdenv.mkDerivation (finalAttrs: {
       -e '/OVMF_CODE_4M.fd/s|ovmfs=(|ovmfs=("${OVMF.firmware}","${OVMF.variables}" |' \
       -e '/cp "''${VARS_IN}" "''${VARS_OUT}"/a chmod +w "''${VARS_OUT}"' \
       -e 's/Icon=.*qemu.svg/Icon=qemu/' \
+      -e 's,\[ -x "\$(command -v smbd)" \],true,' \
       quickemu
   '';