Merge upstream changes from Marlin 2.1.1

buildroot/bin/build_example

@@ -5,6 +5,8 @@
 # Usage: build_example internal config-home config-folder
 #
 
+. mfutil
+
 # Require 'internal' as the first argument
 [[ "$1" == "internal" ]] || { echo "Don't call this script directly, use build_all_examples instead." ; exit 1 ; }
 
@@ -22,8 +24,15 @@ cp "$SUB"/Configuration_adv.h Marlin/ 2>/dev/null
 cp "$SUB"/_Bootscreen.h       Marlin/ 2>/dev/null
 cp "$SUB"/_Statusscreen.h     Marlin/ 2>/dev/null
 
+set -e
+
+# Strip #error lines from Configuration.h
+IFS=$'\n'; set -f
+$SED -i~ -e "20,30{/#error/d}" Marlin/Configuration.h
+rm Marlin/Configuration.h~
+unset IFS; set +f
+
 echo "Building the firmware now..."
-HERE=`dirname "$0"`
-$HERE/mftest -a -n1 || { echo "Failed"; exit 1; }
+$HERE/mftest -s -a -n1 || { echo "Failed"; exit 1; }
 
 echo "Success"