Run FreeBSD CI also against libcxxrt master.

.cirrus.yml

@@ -1,7 +1,7 @@
 freebsd_instance:
   image: freebsd-12-0-release-amd64
 
-task:
+libcxxrt_freebsd_task:
   install_script: pkg install -y cmake ninja llvm80 git
 
   clone_script: |
@@ -16,9 +16,41 @@ task:
     git submodule sync
     git submodule update
 
-  script: |
+  build_script: |
       mkdir Build
       cd Build
       cmake .. -G Ninja -DCMAKE_BUILD_TYPE=Debug -DCMAKE_C_COMPILER=clang80 -DCMAKE_CXX_COMPILER=clang++80
       ninja
-      ctest -j4
+
+  test_script: cd Build && ctest -j4
+
+libcxxrt_master_task:
+  install_script: pkg install -y cmake ninja llvm80 git
+
+  clone_script: |
+    if [ -z "$CIRRUS_PR" ]; then
+      git clone --recursive --branch=$CIRRUS_BRANCH https://x-access-token:${CIRRUS_REPO_CLONE_TOKEN}@github.com/${CIRRUS_REPO_FULL_NAME}.git $CIRRUS_WORKING_DIR
+      git reset --hard $CIRRUS_CHANGE_IN_REPO
+    else
+      git clone --recursive https://x-access-token:${CIRRUS_REPO_CLONE_TOKEN}@github.com/${CIRRUS_REPO_FULL_NAME}.git $CIRRUS_WORKING_DIR
+      git fetch origin pull/$CIRRUS_PR/head:pull/$CIRRUS_PR
+      git reset --hard $CIRRUS_CHANGE_IN_REPO
+    fi
+    git submodule sync
+    git submodule update
+
+  install_libcxxrt_script: |
+      git clone https://github.com/libcxxrt/libcxxrt.git
+      mkdir -p libcxxrt/Build
+      cd libcxxrt/Build
+      cmake .. -G Ninja -DCMAKE_BUILD_TYPE=Debug -DCMAKE_C_COMPILER=clang80 -DCMAKE_CXX_COMPILER=clang++80
+      ninja
+      cp lib/libcxxrt.so /usr/local/lib
+
+  build_script: |
+      mkdir Build
+      cd Build
+      cmake .. -G Ninja -DCMAKE_BUILD_TYPE=Debug -DCMAKE_C_COMPILER=clang80 -DCMAKE_CXX_COMPILER=clang++80
+      ninja
+
+  test_script: cd Build && ctest -j4