w2v-server.pl: fix integer underflow
diff --git a/w2v-server.pl b/w2v-server.pl
old mode 100644
new mode 100755
index e7ad7f5..aa2e46f
--- a/w2v-server.pl
+++ b/w2v-server.pl
@@ -88,7 +88,7 @@
 	float *dist;
 	float *norm;
   long long *pos;
-	unsigned int length;
+	int length;
 } knn;
   
 typedef struct {