build: initial .travis.yml implementation

Refs: ayojs/ayo#14
Refs: ayojs/ayo#75
Co-authored-by: Jeremiah Senkpiel <fishrock123@rocketmail.com>

PR-URL: #21059
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Jon Moss <me@jonathanmoss.me>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Ali Ijaz Sheikh <ofrobots@google.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Daniel Bevenius <daniel.bevenius@gmail.com>
Reviewed-By: Shingo Inoue <leko.noor@gmail.com>
Reviewed-By: Matheus Marchini <matheus@sthima.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>

Author: addaleax

.gitignore

@@ -14,6 +14,7 @@
 !.mailmap
 !.nycrc
 !.remarkrc
+!.travis.yml
 
 core
 vgcore.*

.travis.yml

@@ -0,0 +1,24 @@
+language: cpp
+compiler:
+  - clang
+sudo: false
+cache: ccache
+matrix:
+  include:
+    - os: linux
+      node_js: "latest"
+      script:
+        - NODE=$(which node) make lint-ci
+    - os: linux
+      install:
+        - ./configure
+        - make -j2 V=
+      script:
+        - make -j2 test-ci
+before_install:
+  - export HOMEBREW_NO_AUTO_UPDATE=1 # work around https://github.com/travis-ci/travis-ci/issues/7456
+  - if [ $TRAVIS_OS_NAME = osx ]; then brew install ccache; fi
+  - export PATH="/usr/local/opt/ccache/libexec:$PATH"
+  - export CXX="ccache clang++ -Qunused-arguments"
+  - export CC="ccache clang -Qunused-arguments"
+  - export JOBS=2