build_sdk: fix config overriding

[midnightveil]

Previously duplicate config values would cause multiple
-DKernelOption values being passed on the command line,
and then it was up to CMake shenanigans for how this behaves,
especially if they were incompatible options. Instead, merge
the dictionaries and so later-options are more important.

In order of priority, we have:

• Common kernel options for all arches
• The kernel arch option
• Any common arch-specific kernel options
• Board-specific kernel options

I tested that this makes no changes to the configurations that were build by building the two SDKs, running this script, and then diffing the output, which reported no diffs (that weren't reorderings or different paths)

#!/usr/bin/env bash

set -euo pipefail

build_dir=$(readlink -f "$1")
out_dir_cfg=$(readlink -f "$2")
out_dir_cmake=$(readlink -f "$3")

pushd "$build_dir"

for file in $(fd -t file -uuu gen_config); do
  # zcu102/benchmark/sel4/install/libsel4/include/kernel/gen_config.h
  ofile=$(echo "$file" | sed "s@/@__@g")

  echo "$file --> $ofile"

  cp "$file" "$out_dir_cfg/$ofile"
done;

for file in $(fd -t file -uuu CMakeCache.txt); do
  # x86_64_generic_vtx/smp-release/sel4/build/CMakeCache.txt
  ofile=$(echo "$file" | sed "s@/@__@g")

  echo "$file --> $ofile"

  cp "$file" "$out_dir_cmake/$ofile"
done;


popd