message: Only unity builds for src directory, not for third parties
diff: @@ -71,16 +71,27 @@ def generate_unity_build(entries, idx):
  return ub_file
  def generate_unity_builds(source_list, nsplits):
  + source_list.sort()
  +
  files_per_split = len(source_list) / nsplits
  new_source_files = []
  current_files = []
  idx = 1
  for entry in source_list:
  + if not entry.startswith('src'):
  + new_source_files.append(os.path.join('duckdb', entry))
  + continue
  +
  current_files.append(entry)
  - if len(current_files) > files_per_split or entry == source_list[-1]:
  + if len(current_files) > files_per_split:
  + new_source_files.append(generate_unity_build(current_files, idx))
  + current_files = []
  + idx += 1
  + if len(current_files) > 0:
  new_source_files.append(generate_unity_build(current_files, idx))
  current_files = []
  idx += 1
  +
  return new_source_files
  def convert_backslashes(x):
  