diff --git a/miniz_tdef.c b/miniz_tdef.c
index 51c85f4..d0f0eb7 100644
--- a/miniz_tdef.c
+++ b/miniz_tdef.c
@@ -337,7 +337,7 @@ static void tdefl_optimize_huffman_table(tdefl_compressor *d, int table_num, int
         }                                                                                  \
     }
 
-static mz_uint8 s_tdefl_packed_code_size_syms_swizzle[] = { 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15 };
+static const mz_uint8 s_tdefl_packed_code_size_syms_swizzle[] = { 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15 };
 
 static void tdefl_start_dynamic_block(tdefl_compressor *d)
 {