message: Fix invalid detection of source path in autogen script
  In zsh, realpath $0 returns ".", not an absolute path.
  Thus it is necessary to obtain the absolute path since otherwise cmake "${ROOTDIR}" will look for a CMakeLists.txt in the build directory.
diff: #! /bin/bash
  set -ex
  +if [[ -x "$(command -v realpath)" ]]; then
  + ROOTDIR="$(realpath $(dirname $0))"
  +else
  ROOTDIR="$(dirname $0)"
  +fi
  +
  BUILD_TYPE="${1:-Debug}"
  WORKDIR="build"
  if [[ "${BUILD_TYPE}" != "Debug" ]]; then
  