Update .travis.yml

Updated `.travis.yml` file to add emulated tests for `ARMV6` and `ARMV8`
architectures with `gcc` and `clang`.  Created prebuilt images with
required dependencies. Squashed layers into one.

.travis.yml

@@ -4,11 +4,10 @@ dist: precise
 sudo: true
 language: c
 
-jobs:
+matrix:
   include:
     - &test-ubuntu
       os: linux
-      stage: test
       compiler: gcc
       addons:
         apt:
@@ -59,7 +58,6 @@ jobs:
         - BTYPE="BINARY=32"
 
     - os: linux
-      stage: test
       compiler: gcc
       addons:
         apt:
@@ -80,7 +78,6 @@ jobs:
     # that don't require sudo.
     - &test-alpine
       os: linux
-      stage: test
       dist: trusty
       sudo: true
       language: minimal
@@ -124,7 +121,6 @@ jobs:
 
     - &test-cmake
       os: linux
-      stage: test
       compiler: clang
       addons:
         apt:
@@ -153,7 +149,6 @@ jobs:
 
     - &test-macos
       os: osx
-      stage: test
       osx_image: xcode8
       before_script:
         - COMMON_FLAGS="DYNAMIC_ARCH=1 TARGET=NEHALEM NUM_THREADS=32"
@@ -168,6 +163,42 @@ jobs:
       env:
         - BTYPE="BINARY=32"
 
+    - &emulated-arm
+      dist: trusty
+      sudo: required
+      services: docker
+      env: IMAGE_ARCH=arm32 TARGET_ARCH=ARMV6 COMPILER=gcc
+      name: "Emulated Build for ARMV6 with gcc"
+      before_install: sudo docker run --rm --privileged multiarch/qemu-user-static:register --reset
+      script: |
+        echo "FROM openblas/alpine:${IMAGE_ARCH}
+        COPY . /tmp/openblas
+        RUN mkdir /tmp/openblas/build                             &&  \
+            cd /tmp/openblas/build                                &&  \
+            CC=${COMPILER} cmake -D DYNAMIC_ARCH=OFF                  \
+                                 -D TARGET=${TARGET_ARCH}             \
+                                 -D BUILD_SHARED_LIBS=ON              \
+                                 -D BUILD_WITHOUT_LAPACK=ON           \
+                                 -D BUILD_WITHOUT_CBLAS=ON            \
+                                 -D CMAKE_BUILD_TYPE=Release ../  &&  \
+            cmake --build ." > Dockerfile
+        docker build .
+    - <<: *emulated-arm
+      env: IMAGE_ARCH=arm32 TARGET_ARCH=ARMV6 COMPILER=clang
+      name: "Emulated Build for ARMV6 with clang"
+    - <<: *emulated-arm
+      env: IMAGE_ARCH=arm64 TARGET_ARCH=ARMV8 COMPILER=gcc
+      name: "Emulated Build for ARMV8 with gcc"
+    - <<: *emulated-arm
+      env: IMAGE_ARCH=arm64 TARGET_ARCH=ARMV8 COMPILER=clang
+      name: "Emulated Build for ARMV8 with clang"
+
+  allow_failures:
+    - env: IMAGE_ARCH=arm32 TARGET_ARCH=ARMV6 COMPILER=gcc
+    - env: IMAGE_ARCH=arm32 TARGET_ARCH=ARMV6 COMPILER=clang
+    - env: IMAGE_ARCH=arm64 TARGET_ARCH=ARMV8 COMPILER=gcc
+    - env: IMAGE_ARCH=arm64 TARGET_ARCH=ARMV8 COMPILER=clang
+
 # whitelist
 branches:
   only: