flatbuffers: fix native build with gcc-14 on host

In C++ we cannot have both assignment operator and const member. Since
span::operator= is defined, span::count_ constness must be removed.

Fixes:

FAILED: CMakeFiles/flatc.dir/src/util.cpp.o
ccache flatbuffers/2.0.0/recipe-sysroot-native/usr/bin/aarch64-webos-linux/aarch64-webos-linux-g++ --sysroot=flatbuffers/2.0.0/recipe-sysroot -DFLATBUFFERS_LOCALE_INDEPENDENT=1 -Iflatbuffers/2.0.0/git/include -Iflatbuffers/2.0.0/git/grpc -mbranch-protection=standard -fstack-protector-strong  -O2 -D_FORTIFY_SOURCE=2 -Wformat -Wformat-security -Werror=format-security -Werror=return-type -funwind-tables  --sysroot=flatbuffers/2.0.0/recipe-sysroot  -O2 -pipe -g -feliminate-unused-debug-types -fcanon-prefix-map  -fmacro-prefix-map=flatbuffers/2.0.0/git=/usr/src/debug/flatbuffers/2.0.0  -fdebug-prefix-map=flatbuffers/2.0.0/git=/usr/src/debug/flatbuffers/2.0.0  -fmacro-prefix-map=flatbuffers/2.0.0/build=/usr/src/debug/flatbuffers/2.0.0  -fdebug-prefix-map=flatbuffers/2.0.0/build=/usr/src/debug/flatbuffers/2.0.0  -fdebug-prefix-map=flatbuffers/2.0.0/recipe-sysroot=  -fmacro-prefix-map=flatbuffers/2.0.0/recipe-sysroot=  -fdebug-prefix-map=flatbuffers/2.0.0/recipe-sysroot-native=  -fvisibility-inlines-hidden  -fPIC -DNDEBUG -MD -MT CMakeFiles/flatc.dir/src/util.cpp.o -MF CMakeFiles/flatc.dir/src/util.cpp.o.d -o CMakeFiles/flatc.dir/src/util.cpp.o -c flatbuffers/2.0.0/git/src/util.cpp
In file included from ../git/include/flatbuffers/util.h:23,
                 from ../git/src/util.cpp:44:
../git/include/flatbuffers/stl_emulation.h: In member function 'constexpr flatbuffers::span<T, Extent>& flatbuffers::span<T, Extent>::operator=(const flatbuffers::span<T, Extent>&)':
../git/include/flatbuffers/stl_emulation.h:549:12: error: assignment of read-only member 'flatbuffers::span<T, Extent>::count_'
  549 |     count_ = other.count_;
      |     ~~~~~~~^~~~~~~~~~~~~~

Signed-off-by: Martin Jansa <martin.jansa@gmail.com>
Signed-off-by: Armin Kuster <akuster808@gmail.com>

2 files changed, 30 insertions, 1 deletions

diff --git a/meta-oe/recipes-devtools/flatbuffers/flatbuffers/0001-C-stl_emulation-span-count_-is-not-const-anymore-722.patch b/meta-oe/recipes-devtools/flatbuffers/flatbuffers/0001-C-stl_emulation-span-count_-is-not-const-anymore-722.patch
new file mode 100644
index 0000000000..0a48c665b5
--- /dev/null
+++ b/meta-oe/recipes-devtools/flatbuffers/flatbuffers/0001-C-stl_emulation-span-count_-is-not-const-anymore-722.patch
@@ -0,0 +1,27 @@
+From 659def02b6432b62220ed41d7c137dcfd9dfe024 Mon Sep 17 00:00:00 2001
+From: avaliente-bc <56400759+avaliente-bc@users.noreply.github.com>
+Date: Wed, 6 Apr 2022 21:27:37 +0200
+Subject: [PATCH] [C++] stl_emulation span::count_ is not const anymore (#7226)
+ (#7227)
+
+In C++ we cannot have both assignment operator and const member. Since
+span::operator= is defined, span::count_ constness must be removed.
+---
+Upstream-Status: Backport [https://github.com/google/flatbuffers/commit/20aad0c41e1252b04c72111c3eb221280a9c2009]
+
+ include/flatbuffers/stl_emulation.h | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/include/flatbuffers/stl_emulation.h b/include/flatbuffers/stl_emulation.h
+index 44e9ccbfa..cac87db65 100644
+--- a/include/flatbuffers/stl_emulation.h
++++ b/include/flatbuffers/stl_emulation.h
+@@ -629,7 +629,7 @@ class span FLATBUFFERS_FINAL_CLASS {
+  private:
+   // This is a naive implementation with 'count_' member even if (Extent != dynamic_extent).
+   pointer const data_;
+-  const size_type count_;
++  size_type count_;
+ };
+ 
+  #if !defined(FLATBUFFERS_SPAN_MINIMAL)
diff --git a/meta-oe/recipes-devtools/flatbuffers/flatbuffers_2.0.0.bb b/meta-oe/recipes-devtools/flatbuffers/flatbuffers_2.0.0.bb
index 44478ea0b2..1ffb28a198 100644
--- a/meta-oe/recipes-devtools/flatbuffers/flatbuffers_2.0.0.bb
+++ b/meta-oe/recipes-devtools/flatbuffers/flatbuffers_2.0.0.bb
@@ -14,7 +14,9 @@ RDEPENDS:${PN}-dev += "${PN}-compiler"
 LIC_FILES_CHKSUM = "file://LICENSE.txt;md5=3b83ef96387f14655fc854ddc3c6bd57"
 
 SRCREV = "a9a295fecf3fbd5a4f571f53b01f63202a3e2113"
-SRC_URI = "git://github.com/google/flatbuffers.git;branch=master;protocol=https"
+SRC_URI = "git://github.com/google/flatbuffers.git;branch=master;protocol=https \
+    file://0001-C-stl_emulation-span-count_-is-not-const-anymore-722.patch \
+"
 S = "${WORKDIR}/git"
 
 CVE_CHECK_IGNORE += "CVE-2020-35864"