ci: set the installation prefix once

.gitlab-ci.yml

@@ -123,6 +123,7 @@ include:
     LIBCHECK_ROOT: ${CI_PROJECT_DIR}/libcheck
     LIBCHECK_URL: https://github.com/libcheck/check/releases/download/0.15.2/check-0.15.2.tar.gz
     LIBCHECK_SHA256: a8de4e0bacfb4d76dd1c618ded263523b53b85d92a146d8835eb1a52932fa20a
+    INSTALL_PREFIX: ${CI_PROJECT_DIR}/install
     WARNINGS_AWK_SCRIPT: '/warning/ || /WARNING/ || /Warning/'
     BUILD_LOG: ${CI_PROJECT_DIR}/build.log
   before_script:
@@ -193,7 +194,7 @@ include:
       --with-check-root="${LIBCHECK_ROOT}"
       --enable-python
       --enable-maintainer-mode="${enable_maintainer_mode}"
-      --prefix="${CI_PROJECT_DIR}/install"
+      --prefix="${INSTALL_PREFIX}"
       ${CONFIG_EXTRA_ARGS}
     - make --output-sync=target check AM_COLOR_TESTS=no TESTS= 2>&1 | tee "${BUILD_LOG}"
     - make --silent --keep-going check
@@ -219,13 +220,13 @@ include:
       -DBUILD_TESTING:BOOL=ON
       -DCheck_ROOT="${LIBCHECK_ROOT}"
       -DMTIME_ENABLE_PYTHON:BOOL=ON
-      -DCMAKE_INSTALL_PREFIX:PATH="${CI_PROJECT_DIR}/install"
+      -DCMAKE_INSTALL_PREFIX:PATH="${INSTALL_PREFIX}"
       -G"${CMAKE_GENERATOR}"
       ${CMAKE_EXTRA_ARGS}
     - ${MAKE_CMD} 2>&1 | tee "${BUILD_LOG}"
     - ${MAKE_CMD} test
     - ${MAKE_CMD} install
-    - py_lib_prefix=$(dirname $(find "${CI_PROJECT_DIR}/install" -path '*/mtime/__init__.py' -exec dirname {} + -quit))
+    - py_lib_prefix=$(dirname $(find "${INSTALL_PREFIX}" -path '*/mtime/__init__.py' -exec dirname {} + -quit))
     - PYTHONPATH="${py_lib_prefix}${PYTHONPATH+":${PYTHONPATH}"}" python3 test/test_python.sh
     - !reference [.common, script]
   artifacts: