Re-add memset() that seemed redundant but is necessary in case of GC.
diff --git a/ruby/ext/google/protobuf_c/message.c b/ruby/ext/google/protobuf_c/message.c
index 4dd68f4..0e0272f 100644
--- a/ruby/ext/google/protobuf_c/message.c
+++ b/ruby/ext/google/protobuf_c/message.c
@@ -70,6 +70,9 @@
msg = (MessageHeader*)ALLOC_N(uint8_t,
sizeof(MessageHeader) + desc->layout->size);
+ // Required in case a GC happens before layout_init().
+ memset(msg, 0, desc->layout->size);
+
// We wrap first so that everything in the message object is GC-rooted in case
// a collection happens during object creation in layout_init().
ret = TypedData_Wrap_Struct(klass, &Message_type, msg);
