adding new ubuntu-prerequisite.sh script

notes and typo

ubuntu-prerequisite.sh

@@ -0,0 +1,37 @@
+#!/bin/bash
+
+# Copyright (c) Hin-Tak Leung 2020
+#
+# Overview:
+#   This script compiles and install the Broadcom VideoCore tools,
+#   configure the dynamic loader for the non-standard library location,
+#   and update the loader cache.
+#
+#   A few steps explicitly requires root privilege, which are
+#   marked with "sudo". The rest is just checking for duplicate/previous
+#   action.
+#
+#   This derived from my command history on ubuntu 20.04.1 .YMMV
+
+sudo apt install -y git gcc make alsa-utils cmake
+
+git clone git://github.com/raspberrypi/userland.git
+pushd userland/
+
+arch=$(uname -m)
+if [[ "$arch" =~ aarch64 ]]; then
+    ./buildme --aarch64
+else
+    ./buildme
+fi
+# ./buildme already includes "sudo make install" at the end
+
+popd
+
+# matches Raspbian's location:
+if [ ! -f /etc/ld.so.conf.d/00-vmcs.conf ] ; then
+    echo "/opt/vc/lib" | sudo tee -a /etc/ld.so.conf.d/00-vmcs.conf
+    sudo ldconfig -v
+else
+    echo "/etc/ld.so.conf.d/00-vmcs.conf exists - no need to update ld.cache!"
+fi