Add a nightly FreeBSD Cirrus-CI task

Author: gnzlbg

.cirrus.yml

@@ -2,13 +2,25 @@ freebsd_instance:
   image: freebsd-11-1-release-amd64
 
 task:
-  # This name gets reported as a build status in GitHub
   name: stable x86_64-unknown-freebsd
   setup_script:
     - pkg install -y curl
     - curl https://sh.rustup.rs -sSf --output rustup.sh
     - sh rustup.sh -y
+    - . $HOME/.cargo/env
+    - rustup default stable
+  test_script:
+    - . $HOME/.cargo/env
+    - sh ci/run.sh x86_64-unknown-freebsd
+
+task:
+  name: nightly x86_64-unknown-freebsd
+  setup_script:
+    - pkg install -y curl
+    - curl https://sh.rustup.rs -sSf --output rustup.sh
+    - sh rustup.sh -y
+    - . $HOME/.cargo/env
+    - rustup default nightly
   test_script:
     - . $HOME/.cargo/env
-    - cd libc-test
-    - cargo test
+    - sh ci/run.sh x86_64-unknown-freebsd