Change build toolchain for go to clang

Also adds helpful go-clean command.

mobile/build.sbt

@@ -39,6 +39,12 @@ libraryDependencies ++=
   "net.glxn.qrgen" % "android" % "2.0" ::
   Nil
 
+lazy val goClean = TaskKey[Unit]("go-clean", "Clean go build dependencies")
+goClean := {
+  IO.delete(baseDirectory(base => base / "src/overture/.deps").value)
+  IO.delete(baseDirectory(base => base / "src/main/jni/overture").value)
+}
+
 lazy val goBuild = TaskKey[Unit]("go-build", "Build go and overture")
 goBuild := {
   Process(Seq("mobile/src/overture/make.bash", minSdkVersion.value)) ! streams.value.log match {

mobile/src/overture/make.bash

@@ -4,7 +4,7 @@ function try () {
 "$@" || exit -1
 }
 
-[ -z "$ANDROID_NDK_HOME" ] && ANDROID_NDK_HOME=~/android-ndk-r12b
+[ -z "$ANDROID_NDK_HOME" ] && ANDROID_NDK_HOME=$ANDROID_HOME/ndk-bundle
 
 DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
 MIN_API=$1
@@ -15,13 +15,13 @@ ANDROID_ARM_TOOLCHAIN=$DEPS/android-toolchain-${MIN_API}-arm
 ANDROID_ARM64_TOOLCHAIN=$DEPS/android-toolchain-21-arm64
 ANDROID_X86_TOOLCHAIN=$DEPS/android-toolchain-${MIN_API}-x86
 
-ANDROID_ARM_CC=$ANDROID_ARM_TOOLCHAIN/bin/arm-linux-androideabi-gcc
+ANDROID_ARM_CC=$ANDROID_ARM_TOOLCHAIN/bin/arm-linux-androideabi-clang
 ANDROID_ARM_STRIP=$ANDROID_ARM_TOOLCHAIN/bin/arm-linux-androideabi-strip
 
-ANDROID_ARM64_CC=$ANDROID_ARM64_TOOLCHAIN/bin/aarch64-linux-android-gcc
+ANDROID_ARM64_CC=$ANDROID_ARM64_TOOLCHAIN/bin/aarch64-linux-android-clang
 ANDROID_ARM64_STRIP=$ANDROID_ARM64_TOOLCHAIN/bin/aarch64-linux-android-strip
 
-ANDROID_X86_CC=$ANDROID_X86_TOOLCHAIN/bin/i686-linux-android-gcc
+ANDROID_X86_CC=$ANDROID_X86_TOOLCHAIN/bin/i686-linux-android-clang
 ANDROID_X86_STRIP=$ANDROID_X86_TOOLCHAIN/bin/i686-linux-android-strip
 
 try mkdir -p $DEPS $TARGET/armeabi-v7a $TARGET/x86 $TARGET/arm64-v8a