I18N::Langinfo: Add note to pod

For the last several releases of Perl, the items listed in the note were
always those from the C locale, regardless of the real one.  Before
that, it was even more buggy, whether you got the C locale or the real
one was complicated.

ext/I18N-Langinfo/Langinfo.pm

@@ -72,7 +72,7 @@ our @EXPORT_OK = qw(
 	YESSTR
 );
 
-our $VERSION = '0.14';
+our $VERSION = '0.15';
 
 XSLoader::load();
 
@@ -174,6 +174,11 @@ you can wrap the import in an eval like this:
 
 By default only the C<langinfo()> function is exported.
 
+=head1 BUGS
+
+Before Perl 5.28, the returned values are unreliable for the C<RADIXCHAR> and
+C<THOUSEP> locale constants.
+
 =head1 SEE ALSO
 
 L<perllocale>, L<POSIX/localeconv>, L<POSIX/setlocale>, L<nl_langinfo(3)>.