Add new function to force use of english, use it in quota module

quota/linux-lib.pl

@@ -122,8 +122,10 @@ if ($_[0]->[4]%2 == 1) {
 			}
 		else {
 			# Fall back to testing by running quotaon
+			&clean_language();
 			$out = &backquote_command(
 				"$config{'user_quotaon_command'} $dir 2>&1");
+			&reset_environment();
 			if ($out =~ /Device or resource busy/i) {
 				# already on..
 				$rv += 1;
@@ -152,8 +154,10 @@ if ($_[0]->[4] > 1) {
 			}
 		else {
 			# Fall back to testing by running quotaon
+			&clean_language();
 			$out = &backquote_command(
 				"$config{'group_quotaon_command'} $dir 2>&1");
+			&reset_environment();
 			if ($out =~ /Device or resource busy/i) {
 				# already on..
 				$rv += 2;
@@ -181,8 +185,10 @@ Internal function to check if the quotaon -p flag is supported.
 sub supports_status
 {
 if (!defined($supports_status_cache{$_[0],$_[1]})) {
+	&clean_language();
 	local $stout = &backquote_command(
 		"$config{$_[1].'_quotaon_command'} -p $_[0] 2>&1");
+	&reset_environment();
 	$supports_status_cache{$_[0],$_[1]} =
 		$stout =~ /is\s+(on|off|enabled|disabled)/ ? $stout : 0;
 	}
@@ -295,8 +301,10 @@ Runs the quotacheck command on some filesytem, and returns 1 on success or
 =cut
 sub run_quotacheck
 {
+&clean_language();
 local $out =&backquote_logged(
 	"$config{'quotacheck_command'} $_[1] $_[0] 2>&1");
+&reset_environment();
 return $? || $out =~ /cannot guess|cannot remount|cannot find|please stop/i ? 0 : 1;
 }
 

web-lib-funcs.pl

@@ -7082,6 +7082,21 @@ if (%UNCLEAN_ENV) {
 	}
 }
 
+=head2 clean_language
+
+Sets all language and locale-related environment variables to US english, to
+ensure that commands run output in the expected language. Can be reverted by
+reset_environment.
+
+=cut
+sub clean_language
+{
+%UNCLEAN_ENV = %ENV;
+$ENV{'LANG'} = '';
+$ENV{'LC_ALL'} = '';
+$ENV{'LOCALE'} = '';
+}
+
 =head2 progress_callback
 
 Never called directly, but useful for passing to &http_download to print