Initial commit. Unusable Marlin 2.0.5.3 core without any custimization.

buildroot/bin/opt_set

@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+
+# exit on first failure
+set -e
+
+SED=$(which gsed || which sed)
+
+# Logic for returning nonzero based on answer here: https://stackoverflow.com/a/15966279/104648
+eval "${SED} -i '/\(\/\/\)*\([[:blank:]]*\)\(#define \b${1}\b\).*$/{s//\2\3 ${2}/;h};\${x;/./{x;q0};x;q9}' Marlin/Configuration.h" ||
+eval "${SED} -i '/\(\/\/\)*\([[:blank:]]*\)\(#define \b${1}\b\).*$/{s//\2\3 ${2}/;h};\${x;/./{x;q0};x;q9}' Marlin/Configuration_adv.h" ||
+eval "echo '#define ${@}' >>Marlin/Configuration_adv.h" ||
+(echo "ERROR: opt_set Can't set or add ${1}" >&2 && exit 9)