Add an Android crossbuild on OSX

azure-pipelines.yml

@@ -137,3 +137,18 @@ jobs:
       source /opt/intel/oneapi/setvars.sh
       make CC=/usr/local/opt/llvm/bin/clang FC=ifort
  
+- job: OSX_NDK_ARMV7
+  pool:
+     vmImage: 'macOS-10.15'
+  variables:
+     ANDROID_NDK_HOME: /usr/local/share/android-ndk
+     PATH: $(ANDROID_NDK_HOME)/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86_64/bin:$(ANDROID_NDK_HOME)/toolchains/llvm/prebuilt/linux-x86_64/bin:$PATH
+     LDFLAGS: -L$(ANDROID_NDK_HOME)/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86_64/lib/gcc/arm-linux-androideabi/4.9.x
+     CLANG_FLAGS: "-target arm-linux-androideabi -marm -mfpu=vfp -mfloat-abi=softfp --sysroot $(ANDROID_NDK_HOME)/platforms/android-23/arch-arm -gcc-toolchain $(ANDROID_NDK_HOME)/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86_64/"
+  steps:   
+  - script: | 
+      brew update
+      brew install --cask android-ndk
+      ls /usr/local/share/android-ndk/toolchains
+      make TARGET=ARMV7 ONLY_CBLAS=1 AR=ar CC="clang ${CLANG_FLAGS}" HOSTCC=gcc ARM_SOFTFP_ABI=1 -j4
+