gitlab-ci: init environment with per-CMAKE_CONFIGURATION shell scripts

.gitlab/ci/env.sh

@@ -0,0 +1,14 @@
+quietly() {
+  readonly log="/tmp/quietly-$RANDOM.log"
+  if ! "$@" >"$log" 2>&1; then
+    ret=$?
+    cat "$log"
+    rm -f "$log"
+    exit $ret
+  fi
+  rm -f "$log"
+}
+
+if test -r ".gitlab/ci/env_${CMAKE_CONFIGURATION}.sh"; then
+  source ".gitlab/ci/env_${CMAKE_CONFIGURATION}.sh"
+fi

.gitlab/os-linux.yml

@@ -195,6 +195,7 @@
 ## Linux-specific scripts
 
 .before_script_linux: &before_script_linux
+    - source .gitlab/ci/env.sh
     - .gitlab/ci/cmake.sh
     - .gitlab/ci/ninja.sh
     - export PATH=$PWD/.gitlab:$PWD/.gitlab/cmake/bin:$PATH
@@ -251,6 +252,7 @@
     stage: build
 
     script:
+        - source .gitlab/ci/env.sh
         # Bootstrap.
         - mkdir -p build/
         # Exclude documentation.  A job dependency provides it for packaging.