unicode: check $LC_CTYPE too to detect Unicode mode

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/shell/ash.c b/shell/ash.c
index 90f2224..d696bbd 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -9659,6 +9659,7 @@
 		 */
 		{
 			const char *s = lookupvar("LC_ALL");
+			if (!s) s = lookupvar("LC_CTYPE");
 			if (!s) s = lookupvar("LANG");
 			reinit_unicode(s);
 		}