Add cross arch tests

.travis.yml

@@ -1,6 +1,7 @@
 language: rust
 cache: cargo
 dist: xenial
+services: docker
 
 rust:
   - stable
@@ -10,31 +11,41 @@ rust:
 env:
   global:
     - secure: "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"
+  matrix:
+    - TARGET="x86_64-unknown-linux-gnu"
+    - TARGET="mips-unknown-linux-gnu"
+    - TARGET="mipsel-unknown-linux-gnu"
+    - TARGET="mips64-unknown-linux-gnuabi64"
+    - TARGET="mips64el-unknown-linux-gnuabi64"
+    - TARGET="aarch64-unknown-linux-gnu"
+
+before_install:
+  - command -v cross 1>/dev/null || cargo install cross
 
 script:
-  - cargo build --verbose --all
-  - cargo test --verbose --all
+  - cross build --target $TARGET --verbose --all
+  - cross test --target $TARGET --verbose --all
 
 matrix:
   allow_failures:
     - rust: nightly
   fast_finish: true
   include:
-  - name: Rustfmt
-    rust: stable
-    env:
-      - SKIP_DEPLOY="yes"
-    script:
-      - rustup component add rustfmt-preview
-      - cargo fmt --all -- --check
-  - name: Clippy
-    rust: stable
-    env:
-      - SKIP_DEPLOY="yes"
-    before_script:
-      - rustup component add clippy-preview
-    script:
-      - cargo clippy --all-targets --all-features -- -D warnings
+    - name: Rustfmt
+      rust: stable
+      env:
+        - SKIP_DEPLOY="yes"
+      script:
+        - rustup component add rustfmt-preview
+        - cargo fmt --all -- --check
+    - name: Clippy
+      rust: stable
+      env:
+        - SKIP_DEPLOY="yes"
+      before_script:
+        - rustup component add clippy-preview
+      script:
+        - cargo clippy --all-targets --all-features -- -D warnings
 
 deploy:
   # Create new crates.io package