Add Windows build config to Travis

.travis.yml

@@ -2,7 +2,8 @@ language: go
 sudo: false
 dist: trusty
 env:
-  HUGO_BUILD_TAGS="extended"
+  global:
+  - HUGO_BUILD_TAGS="extended"
 git:
   depth: false
 go:
@@ -11,10 +12,15 @@ go:
 os:
   - linux
   - osx
+  - windows
 matrix:
   allow_failures:
     - go: tip
   fast_finish: true
+  exclude:
+  - os: windows
+    go: tip
+
 install:
   - mkdir -p $HOME/src
   - mv $HOME/gopath/src/github.com/gohugoio/hugo $HOME/src
@@ -28,6 +34,11 @@ script:
   - mage -v hugo
   - ./hugo -s docs/
   - ./hugo --renderToMemory -s docs/
+  - df -h
+
 before_install:
+  - df -h
+    # https://travis-ci.community/t/go-cant-find-gcc-with-go1-11-1-on-windows/293/5
+  - if [[ "$TRAVIS_OS_NAME" == "windows" ]]; then choco install mingw -y; export PATH=/c/tools/mingw64/bin:"$PATH"; fi
   - gem install asciidoctor
   - type asciidoctor