!13 fix some bug: fix-undefined-behaviour adn support-conform-for-vector-of-unions

From: @YeFeng_24
Reviewed-by: @overweight
Signed-off-by: @overweight

0005-fix-undefined-behaviour.patch

@@ -0,0 +1,27 @@
+From 57ee742cb1d2a2902dd5e00af5da9293aa11326c Mon Sep 17 00:00:00 2001
+From: yefeng <yefeng24@huawei.com>
+Date: Wed, 17 Nov 2021 14:49:42 +0800
+Subject: [PATCH 1/2] fix undefined behaviour
+
+---
+ include/flatbuffers/flatbuffers.h | 4 +++-
+ 1 file changed, 3 insertions(+), 1 deletion(-)
+
+diff --git a/include/flatbuffers/flatbuffers.h b/include/flatbuffers/flatbuffers.h
+index e652e40..42c4fa8 100644
+--- a/include/flatbuffers/flatbuffers.h
++++ b/include/flatbuffers/flatbuffers.h
+@@ -1808,7 +1808,9 @@ class FlatBufferBuilder {
+   template<typename T>
+   Offset<Vector<const T *>> CreateVectorOfStructs(const T *v, size_t len) {
+     StartVector(len * sizeof(T) / AlignOf<T>(), AlignOf<T>());
+-    PushBytes(reinterpret_cast<const uint8_t *>(v), sizeof(T) * len);
++    if (len > 0) {
++      PushBytes(reinterpret_cast<const uint8_t *>(v), sizeof(T) * len);
++    }
+     return Offset<Vector<const T *>>(EndVector(len));
+   }
+ 
+-- 
+2.17.1
+

flatbuffers.spec

@@ -5,7 +5,7 @@
 %endif
 Name:                flatbuffers
 Version:             2.0.0
-Release:             3
+Release:             4
 Summary:             Memory efficient serialization library
 License:             Apache-2.0
 URL:                 https://github.com/google/flatbuffers
@@ -17,6 +17,7 @@ Patch0:              0001-Fix-compiler-warning-Wredundant-parens.patch
 Patch1:              0002-typo-fixes-in-comments.patch
 Patch2:              0003-Changes-to-support-binary-schema-file-loading-and-pa.patch
 Patch3:              0004-output-errors-instead-of-stdout.patch
+Patch4:              0005-fix-undefined-behaviour.patch
 
 BuildRequires:       gcc-c++ cmake >= 2.8.9
 Provides:            bundled(grpc)
@@ -75,7 +76,10 @@ make test
 %{_libdir}/cmake/flatbuffers/*.cmake
 
 %changelog
-* Wed Nov 15 2021 yefeng <yefeng24@huawei.com> - 2.0.0-3
+* Wed Nov 17 2021 yefeng <yefeng24@huawei.com> - 2.0.0-4
+- fix undefined behaviour
+
+* Mon Nov 15 2021 yefeng <yefeng24@huawei.com> - 2.0.0-3
 - output errors instead of stdout, Typo fixes in comments and Changes to support binary schema file
 
 * Wed Nov 11 2021 yefeng <yefeng24@huawei.com> - 2.0.0-2