Enable Kali Purple installer theme

Other things that I tried, but that didn't work, below:

I tried adding the preseed to simple-cdd/profiles/kali-purple.preseed,
however that didn't work, I guess that this preseed file is loaded only
later during installation, and that at this point the GUI was already
loaded and it's too late to set the theme.

I also tried to do this in simple-cdd.conf:

  # Theming
  if echo " $profiles " | grep -q " kali-purple "; then
    export KERNEL_PARAMS="${KERNEL_PARAMS} debian-installer/theme=Clearlooks-Purple "
  fi

But it doesn't work, seemingly 'profiles' is not set when simple-cdd
loads the conf, and even though we build with the command:

    build-simple-cdd [...] --profiles "$profiles" [...]

Given the fact that uppercase variables are exported, and what we
actually want to change is KERNEL_PARAMS, it seems that the most
straightforward is just to preset it from build.sh.

build.sh

@@ -329,6 +329,7 @@ case "$IMAGE_TYPE" in
 			export DISKTYPE="BD"
 			profiles="kali kali-purple"
 			auto_profiles="kali kali-purple"
+			export KERNEL_PARAMS="debian-installer/theme=Clearlooks-Purple"
 		else    # plain installer
 			export DISKTYPE="BD"
 			profiles="kali offline"
@@ -337,6 +338,7 @@ case "$IMAGE_TYPE" in
 		debug "DISKTYPE: $DISKTYPE"
 		debug "profiles: $profiles"
 		debug "auto_profiles: $auto_profiles"
+		[ -v KERNEL_PARAMS ] && debug "KERNEL_PARAMS: $KERNEL_PARAMS"
 
 		if [ -e .mirror ]; then
 			kali_mirror=$(cat .mirror)

kali-config/installer-purple/packages

@@ -5,6 +5,7 @@
 # in the installer ISO.
 # For the complete list see: https://tools.kali.org/kali-metapackages
 kali-system-core
+kali-themes-purple  # temporary, until we do it a better way
 
 # Tools
 kali-tools-detect

simple-cdd/simple-cdd.conf

@@ -50,7 +50,7 @@ security_mirror=""
 updates_mirror=""
 
 # Add kernel parameter to disable
-export KERNEL_PARAMS="net.ifnames=0 "
+export KERNEL_PARAMS="${KERNEL_PARAMS} net.ifnames=0 "
 
 # Kernel and architecture related
 if [ "$ARCH" = "i386" ]; then