Support cross compiling for aarch64 (#52)

build-aarch64-linux-gnu.sh

@@ -0,0 +1,49 @@
+#!/usr/bin/env bash
+
+if ! command -v aarch64-linux-gnu-gcc  &> /dev/null; then
+  echo "Please install a toolchain for cross-compiling."
+  echo "You can refer to: "
+  echo "  https://k2-fsa.github.io/sherpa/onnx/install/aarch64-embedded-linux.html"
+  echo "for help."
+  exit 1
+fi
+
+set -ex
+
+dir=build-aarch64-linux-gnu
+mkdir -p $dir
+cd $dir
+
+if [ ! -f alsa-lib/src/.libs/libasound.so ]; then
+  echo "Start to cross-compile alsa-lib"
+  if [ ! -d alsa-lib ]; then
+    git clone --depth 1 https://github.com/alsa-project/alsa-lib
+  fi
+  # If it shows:
+  #  ./gitcompile: line 79: libtoolize: command not found
+  # Please use:
+  #  sudo apt-get install libtool m4 automake
+  #
+  pushd alsa-lib
+  CC=aarch64-linux-gnu-gcc ./gitcompile --host=aarch64-linux-gnu
+  popd
+  echo "Finish cross-compiling alsa-lib"
+fi
+
+export CPLUS_INCLUDE_PATH=$PWD/alsa-lib/include:$CPLUS_INCLUDE_PATH
+export SHERPA_ONNX_ALSA_LIB_DIR=$PWD/alsa-lib/src/.libs
+
+cmake \
+  -DCMAKE_INSTALL_PREFIX=./install \
+  -DCMAKE_BUILD_TYPE=Release \
+  -DBUILD_SHARED_LIBS=OFF \
+  -DSHERPA_ONNX_ENABLE_TESTS=OFF \
+  -DSHERPA_ONNX_ENABLE_PYTHON=OFF \
+  -DCMAKE_TOOLCHAIN_FILE=../toolchains/aarch64-linux-gnu.toolchain.cmake \
+  ..
+
+make VERBOSE=1 -j4
+make install/strip
+
+# Enable it if only needed
+# cp -v $SHERPA_ONNX_ALSA_LIB_DIR/libasound.so* ./install/lib/