ash: fix a SEGV in ${#1}

function                                             old     new   delta
varvalue                                             760     805     +45
evalvar                                              648     603     -45

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/shell/ash.c b/shell/ash.c
index 90fb00f..c5ad969 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -6746,6 +6746,14 @@
 		len = strlen(p);
 		if (!(subtype == VSPLUS || subtype == VSLENGTH))
 			memtodest(p, len, syntax, quotes);
+#if ENABLE_UNICODE_SUPPORT
+		if (subtype == VSLENGTH && len > 0) {
+			reinit_unicode_for_ash();
+			if (unicode_status == UNICODE_ON) {
+				len = unicode_strlen(p);
+			}
+		}
+#endif
 		return len;
 	}
 
@@ -6829,15 +6837,7 @@
 		varunset(p, var, 0, 0);
 
 	if (subtype == VSLENGTH) {
-		ssize_t n = varlen;
-		if (n > 0) {
-			reinit_unicode_for_ash();
-			if (unicode_status == UNICODE_ON) {
-				const char *val = lookupvar(var);
-				n = unicode_strlen(val);
-			}
-		}
-		cvtnum(n > 0 ? n : 0);
+		cvtnum(varlen > 0 ? varlen : 0);
 		goto record;
 	}