makedef.pl: Don't use locale items unless using locale

If we are configured to not look at locales at all, we shouldn't be
looking at threaded locales nor POSIX 2008 ones.

This commit fixes a situation that is not likely at all to show up in
real life, but I stumbled across it in testing weird configurations.

makedef.pl

@@ -156,11 +156,15 @@ BEGIN
 
 # https://en.wikipedia.org/wiki/Microsoft_Visual_C%2B%2B#Internal_version_numbering
 my $cctype = $ARGS{CCTYPE} =~ s/MSVC//r;
-if ($define{USE_ITHREADS} && ! $define{NO_LOCALE_THREADS}) {
+if (   $define{USE_ITHREADS}
+    && $define{USE_LOCALE}
+    && ! $define{NO_LOCALE_THREADS})
+{
     $define{USE_LOCALE_THREADS} = 1;
 }
 
 if (   $define{HAS_POSIX_2008_LOCALE}
+    && $define{USE_LOCALE}
     && (! $define{HAS_SETLOCALE} || (     $define{USE_LOCALE_THREADS}
                                      && ! $define{NO_POSIX_2008_LOCALE})
                                      && ! $define{NO_THREAD_SAFE_LOCALE}))