https://github.com/kjn/lbzip2/pull/25

From d570020ade2add591b97e61927545a005a2d4a6f Mon Sep 17 00:00:00 2001
From: Matt Turner <mattst88@gmail.com>
Date: Wed, 7 Aug 2019 11:47:04 -0700
Subject: [PATCH] Align zero-length array to avoid unaligned accesses

When make_tree() creates the left-justified base table (uint64_t *B)
it does so with 64-bit stores:

    B[k] = sofar;

But B points to memory in the zero-length array "uint32_t tt[0]" at the
end of struct decoder_state. Since tt's type is uint32_t, it is only
aligned to a four byte boundary, and so the 64-bit store in make_tree()
causes an unaligned trap on strict platforms like sparc.
---
 src/decode.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/decode.h b/src/decode.h
index c9a9086..7c0ca3f 100644
--- a/src/decode.h
+++ b/src/decode.h
@@ -62,7 +62,7 @@ struct decoder_state {
   uint8_t rle_char;             /* current character */
   uint8_t rle_prev;             /* prevoius character */
 
-  uint32_t tt[0];
+  uint32_t tt[0] __attribute__((aligned (8)));
 };