aarch64 cross compile example on x86 ubuntu

corsscompile.make.sh

#!/bin/env bash

## SYSROOT was generated by 
# sudo apt-get install qemu-user qemu-user-static debootstrap schroot
# sudo debootstrap --arch=arm64 focal /srv/chroot/arm64 http://ports.ubuntu.com/
## 

SYSROOT=/srv/chroot/arm64

# module file for crossbuild complier
# /opt/admin/module/files/crossbuild/crossbuild/7.5.0:
# prepend-path    PATH /opt/software/crossbuild/crossbuild/7.5.0/gcc-linaro-7.5.0-2019.12-x86_64_aarch64-linux-gnu/bin
# prepend-path    LD_LIBRARY_PATH /opt/software/crossbuild/crossbuild/7.5.0/gcc-linaro-7.5.0-2019.12-x86_64_aarch64-linux-gnu/lib
# prepend-path    CPATH /opt/software/crossbuild/crossbuild/7.5.0/gcc-linaro-7.5.0-2019.12-x86_64_aarch64-linux-gnu/include
# prepend-path    MANPATH /opt/software/crossbuild/crossbuild/7.5.0/gcc-linaro-7.5.0-2019.12-x86_64_aarch64-linux-gnu/share

module load crossbuild/7.5.0

CC=aarch64-linux-gnu-gcc
CXX=aarch64-linux-gnu-c++
LD=aarch64-linux-gnu-ld
AR=aarch64-linux-gnu-ar
AS=aarch64-linux-gnu-as
NM=aarch64-linux-gnu-gcc-nm
STRIP=aarch64-linux-gnu-strip
RANLIB=aarch64-linux-gnu-ranlib
OBJDUMP=aarch64-linux-gnu-objdump

# this is inside of source code build dir, you may need to first 
# tar -xvf <src.tar.gz>
# cd src
# mkdir build && cd build
# and then add this file to build.sh then excute it
../configure \
--build=x86_64-linux-gnu \
--host=aarch64-linux-gnu \
--target=aarch64-linux-gnu \
--cache-file=aarch64-linux-gnu.cache \
--with-sysroot=${SYSROOT} \
--prefix=`pwd`/dist

make -j $(nproc)
make install
# finally you will see the compile result in ./dist dir, and then you can install to the target machine