Forcing locale "C" to avoid grep ambiguities and locale bugs

xorriso-dd-target/xorriso-dd-target

@@ -5,6 +5,9 @@
 # Thomas Schmitt <scdbackup@gmx.net>
 # Provided under GPL version 2 or later.
 
+export LANG=C
+export LC_ALL=C
+
 # Check whether we are on GNU/Linux
 if uname -s | grep -v '^Linux' >/dev/null
 then
@@ -139,7 +142,7 @@ round_down_div_million() {
 check_parameter() {
  if test "$2" = "device_name"
  then
-   if echo "$1" | grep '[^A-za-z0-9_/-]' >/dev/null
+   if echo "$1" | grep '[^A-Za-z0-9_/-]' >/dev/null
    then
      echo "SORRY: Given device name contains unexpected character. Ok: [A-za-z0-9_/-]" >&2
      exit 12