machine:
  environment:
    INSTALL_PREFIX_DIR: ~/opt
    INSTALL_PREFIX_BIN_DIR: ${INSTALL_PREFIX_DIR}/bin
    PATH: ${INSTALL_PREFIX_BIN_DIR}:${PATH}

checkout:
  post:
    - git submodule sync --recursive
    - git submodule update --recursive --init

dependencies:
  override:
    - vendor-install-tools/install.py meson --installPrefixDir=${INSTALL_PREFIX_BIN_DIR}

test:
  post:
    - meson -v
    - echo 'Does nothing yet'

machine:
  environment:
    INSTALL_PREFIX_DIR: ${HOME}/opt
    INSTALL_PREFIX_BIN_DIR: ${INSTALL_PREFIX_DIR}/bin
    PATH: ${INSTALL_PREFIX_BIN_DIR}:${PATH}

checkout:
  post:
    - git submodule sync --recursive
    - git submodule update --recursive --init

dependencies:
  override:
    - vendor-install-tools/install.py meson --installPrefixDir=${INSTALL_PREFIX_DIR}

test:
  post:
    - meson -v
    - echo 'Does nothing yet'

Use ${HOME} for prefix dir and fix --installPrefixDir
Use ${HOME} for prefix dir and fix --installPrefixDir
