Add arm build checkup

.travis.yml

@@ -14,10 +14,10 @@ matrix:
       rust: beta
       env: GTK=3.22.30
     - os: linux
-      rust: 1.31
+      rust: 1.31.0
       env: GTK=3.4
     - os: linux
-      rust: 1.31
+      rust: 1.31.0
       env: GTK=3.22.30
     - os: osx
       rust: nightly
@@ -37,6 +37,12 @@ matrix:
     # - os: osx
     #   rust: stable
     #   env: GTK=3.22.30
+    - os: linux
+      rust: nightly
+      env: GTK=3.4 ARM=1 OTHER_TARGET="--target armv7-unknown-linux-gnueabihf"
+    - os: linux
+      rust: nightly
+      env: GTK=3.22.30 ARM=1 OTHER_TARGET="--target armv7-unknown-linux-gnueabihf"
 sudo: true
 addons:
   apt:
@@ -46,15 +52,32 @@ before_install:
   - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then brew update; fi
   - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then brew install gtk+3 cairo atk; fi
   - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then export PKG_CONFIG_PATH=/usr/local/lib/pkgconfig:/opt/X11/lib/pkgconfig; fi
+  - if [[ "$ARM" == "1" ]]; then rustup target add armv7-unknown-linux-gnueabihf; fi
 script:
-  - if [ "$TRAVIS_RUST_VERSION" == "nightly" ] && [ "$GTK" == "3.4" ]; then
+  - if [ "$TRAVIS_RUST_VERSION" == "nightly" ] && [ "$GTK" == "3.4" ] && ! [ "$ARM" == "1" ]; then
     make regen_check;
     fi
-  - cargo doc --features "dox"
-  - cargo test --features "subclassing"
+  - if ! [ "$ARM" == "1" ]; then
+    cargo doc --features "dox";
+    fi
+  - if ! [ "$ARM" == "1" ]; then
+    cargo test --features "subclassing";
+    fi
+  - if [ "$ARM" == "1" ]; then
+    PKG_CONFIG_ALLOW_CROSS=1 cargo build $OTHER_TARGET;
+    fi
+  - if [ "$ARM" == "1" ]; then
+    PKG_CONFIG_ALLOW_CROSS=1 cargo build --features subclassing $OTHER_TARGET;
+    fi
   - rustc --version
   - mkdir .cargo
   - echo 'paths = ["."]' > .cargo/config
-  - git clone -q --depth 50 -b pending https://github.com/gtk-rs/examples _examples
-  - cd _examples
-  - ./build_travis.sh
+  - if ! [ "$ARM" == "1" ]; then
+    git clone -q --depth 50 -b pending https://github.com/gtk-rs/examples _examples;
+    fi
+  - if ! [ "$ARM" == "1" ]; then
+    cd _examples;
+    fi
+  - if ! [ "$ARM" == "1" ]; then
+    ./build_travis.sh;
+    fi