maybe add code coverage to the CI

.travis.yml

@@ -1,14 +1,43 @@
 language: rust
+sudo: false
+
 rust:
-  #  - stable  we use a feature flag that precludes this
+  - stable
   - beta
   - nightly
 matrix:
   allow_failures:
+    - rust: stable
     - rust: beta
 script:
   - cargo build --verbose --all
   - cargo test --verbose --all
-before_install:
-  - sudo apt-get -qq update
-  - sudo apt-get install -y libxcb-icccm4-dev libxcb-ewmh-dev libxcb-keysyms1-dev libfontconfig1-dev libfreetype6-dev libegl1-mesa-dev
+
+addons:
+  apt:
+    packages:
+      - libxcb-icccm4-dev
+      - libxcb-ewmh-dev
+      - libxcb-keysyms1-dev
+      - libfontconfig1-dev
+      - libfreetype6-dev
+      - libegl1-mesa-dev
+
+env:
+  global:
+    - RUSTFLAGS="-C link-dead-code"
+
+after_success: |
+  wget https://github.com/SimonKagstrom/kcov/archive/master.tar.gz &&
+  tar xzf master.tar.gz &&
+  cd kcov-master &&
+  mkdir build &&
+  cd build &&
+  cmake .. &&
+  make &&
+  make install DESTDIR=../../kcov-build &&
+  cd ../.. &&
+  rm -rf kcov-master &&
+  for file in target/debug/term-*[^\.d] target/debug/wezterm-*[^\.d]; do mkdir -p "target/cov/$(basename $file)"; ./kcov-build/usr/local/bin/kcov --exclude-pattern=/.cargo,/usr/lib --verify "target/cov/$(basename $file)" "$file"; done &&
+  bash <(curl -s https://codecov.io/bash) &&
+  echo "Uploaded code coverage"