Fix OOB in hb-shape

util/options.cc

diff --git a/util/options.cc b/util/options.cc
index 5ded644..6585eb4 100644
--- a/util/options.cc
+++ b/util/options.cc
@@ -631,7 +631,7 @@
   char buf[BUFSIZ];
   while (fgets (buf, sizeof (buf), fp)) {
     unsigned int bytes = strlen (buf);
-    if (buf[bytes - 1] == '\n') {
+    if (bytes && buf[bytes - 1] == '\n') {
       bytes--;
       g_string_append_len (gs, buf, bytes);
       break;