An updated version of the script here https://freckled.dev/how-to/2019/07/29/create-gcc-crosscompiler/

rpi_cross_compiler.bash

#!/bin/bash

# stop script on first error
set -e

mkdir gcc_for_raspberrypi
cd gcc_for_raspberrypi

# variables that define the result
install_dir="$(pwd)/install"
sysroot_dir="$(pwd)/sysroot"
arch=armv8-a
tune=cortex-a72
gcc_version='10.2.0'
binutils_version='2.35.1'

# mount raspberry root
mkdir sysroot
sshfs -o ro [email protected]:/ ./sysroot

# get sources
curl -Lo binutils.tar.bz2 \
  "https://ftpmirror.gnu.org/binutils/binutils-$binutils_version.tar.bz2"
curl -Lo gcc.tar.xz \
  "https://ftp.wayne.edu/gnu/gcc/gcc-$gcc_version/gcc-$gcc_version.tar.xz"

# build binutils
mkdir binutils_source
cd binutils_source
tar --strip-components 1 -xf ../binutils.tar.bz2
mkdir ../binutils_build
cd ../binutils_build
../binutils_source/configure \
  --prefix="$install_dir" \
  --target=arm-linux-gnueabihf \
  --with-arch=$arch \
  --with-tune=$tune \
  --with-fpu=vfp \
  --with-float=hard \
  --disable-multilib \
  --with-sysroot="$sysroot_dir" \
  --enable-gold=yes \
  --enable-lto
make -j$(nproc)
make install
cd ..

# build gcc
mkdir gcc_source
cd gcc_source
tar --strip-components 1 -xf ../gcc.tar.xz
mkdir ../gcc_build
cd ../gcc_build
../gcc_source/configure \
  --prefix="$install_dir" \
  --target=arm-linux-gnueabihf \
  --with-arch=$arch \
  --with-tune=$tune \
  --with-fpu=vfp \
  --with-float=hard \
  --disable-multilib \
  --with-sysroot="$sysroot_dir" \
  --enable-languages=c,c++,go,d
make -j$(nproc)
make install
cd ..

echo "Successfully compiled 'binutils' and 'gcc'"