This package currently fails to build (at least on the amd64
architecture) with link time optimizations enabled.  For a background
for LTO please see

https://wiki.debian.org/ToolChain/LTO

The goal is to enable this optimization by default in an upcoming
Debian release in dpkg-buildflags for 64bit architectures.  The goal
is to get this package to build with link time optimizations, or to
explicitly disable link time optimizations for this package build.

To reproduce the build failure, enable the lto optimization in
testing/unstable by adding "optimize=+lto" to DEB_BUILD_MAINT_OPTIONS
in the debian/rules file, or if this macro is unset, just set it:

export DEB_BUILD_MAINT_OPTIONS = optimize=+lto

Please try to fix the build with lto enabled, fixing the packaging or
forwarding the issue upstream. If the issue cannot be fixed,
explicitly disallow building the package with lto by adding to your
rules file:

export DEB_BUILD_MAINT_OPTIONS = optimize=-lto

or adding that string to your existing setting of DEB_BUILD_MAINT_OPTIONS.

The full build log can be found at:
http://qa-logs.debian.net/2022/06/09/dpkglto/tinyxml2_9.0.0+dfsg-3.1_unstable_dpkglto.log
The last lines of the build log are at the end of this report.

[...]
make[3]: Entering directory '/<<PKGBUILDDIR>>/build'
cd /<<PKGBUILDDIR>>/build && /usr/bin/cmake -E cmake_depends "Unix Makefiles" /<<PKGBUILDDIR>> /<<PKGBUILDDIR>> /<<PKGBUILDDIR>>/build /<<PKGBUILDDIR>>/build /<<PKGBUILDDIR>>/build/CMakeFiles/xmltest.dir/DependInfo.cmake --color=
Consolidate compiler generated dependencies of target xmltest
make[3]: Leaving directory '/<<PKGBUILDDIR>>/build'
make  -f CMakeFiles/xmltest.dir/build.make CMakeFiles/xmltest.dir/build
make[3]: Entering directory '/<<PKGBUILDDIR>>/build'
make[3]: Nothing to be done for 'CMakeFiles/xmltest.dir/build'.
make[3]: Leaving directory '/<<PKGBUILDDIR>>/build'
[100%] Built target xmltest
make[2]: Leaving directory '/<<PKGBUILDDIR>>/build'
/usr/bin/cmake -E cmake_progress_start /<<PKGBUILDDIR>>/build/CMakeFiles 0
make  -f CMakeFiles/Makefile2 preinstall
make[2]: Entering directory '/<<PKGBUILDDIR>>/build'
make[2]: Nothing to be done for 'preinstall'.
make[2]: Leaving directory '/<<PKGBUILDDIR>>/build'
Install the project...
/usr/bin/cmake -P cmake_install.cmake
-- Install configuration: "None"
-- Installing: /<<PKGBUILDDIR>>/debian/tmp/usr/lib/x86_64-linux-gnu/libtinyxml2.so.9.0.0
-- Installing: /<<PKGBUILDDIR>>/debian/tmp/usr/lib/x86_64-linux-gnu/libtinyxml2.so.9
-- Installing: /<<PKGBUILDDIR>>/debian/tmp/usr/lib/x86_64-linux-gnu/libtinyxml2.so
-- Installing: /<<PKGBUILDDIR>>/debian/tmp/usr/lib/x86_64-linux-gnu/cmake/tinyxml2/tinyxml2-shared-targets.cmake
-- Installing: /<<PKGBUILDDIR>>/debian/tmp/usr/lib/x86_64-linux-gnu/cmake/tinyxml2/tinyxml2-shared-targets-none.cmake
-- Installing: /<<PKGBUILDDIR>>/debian/tmp/usr/lib/x86_64-linux-gnu/cmake/tinyxml2/tinyxml2-config.cmake
-- Installing: /<<PKGBUILDDIR>>/debian/tmp/usr/lib/x86_64-linux-gnu/cmake/tinyxml2/tinyxml2-config-version.cmake
-- Installing: /<<PKGBUILDDIR>>/debian/tmp/usr/include/tinyxml2.h
-- Installing: /<<PKGBUILDDIR>>/debian/tmp/usr/lib/x86_64-linux-gnu/pkgconfig/tinyxml2.pc
make[1]: Leaving directory '/<<PKGBUILDDIR>>/build'
   dh_install -O-Bbuild -O-Scmake
   dh_installdocs -O-Bbuild -O-Scmake
   dh_installchangelogs -O-Bbuild -O-Scmake
   dh_installinit -O-Bbuild -O-Scmake
   dh_perl -O-Bbuild -O-Scmake
   dh_link -O-Bbuild -O-Scmake
   dh_strip_nondeterminism -O-Bbuild -O-Scmake
   dh_compress -O-Bbuild -O-Scmake
   dh_fixperms -O-Bbuild -O-Scmake
   dh_missing -O-Bbuild -O-Scmake
   dh_dwz -O-Bbuild -O-Scmake
   dh_strip -O-Bbuild -O-Scmake
   debian/rules override_dh_makeshlibs
make[1]: Entering directory '/<<PKGBUILDDIR>>'
dh_makeshlibs -- -c4
dpkg-gensymbols: error: some symbols or patterns disappeared in the symbols file: see diff output below
dpkg-gensymbols: warning: debian/libtinyxml2-9/DEBIAN/symbols doesn't match completely debian/libtinyxml2-9.symbols
--- debian/libtinyxml2-9.symbols (libtinyxml2-9_9.0.0+dfsg-3.1_amd64)
+++ dpkg-gensymbolsJkO5y9	2022-06-10 09:08:37.425841245 +0000
@@ -182,7 +182,7 @@
  (c++|regex)"tinyxml2::XMLUtil::ToUnsigned64\(char const\*, unsigned (long )?long\*\)@Base" 8.0.0
  (c++)"tinyxml2::XMLUtil::writeBoolFalse@Base" 8.0.0
  (c++)"tinyxml2::XMLUtil::writeBoolTrue@Base" 8.0.0
- (c++)"typeinfo for tinyxml2::XMLAttribute@Base" 8.0.0
+#MISSING: 9.0.0+dfsg-3.1# (c++)"typeinfo for tinyxml2::XMLAttribute@Base" 8.0.0
  (c++)"typeinfo for tinyxml2::XMLComment@Base" 8.0.0
  (c++)"typeinfo for tinyxml2::XMLDeclaration@Base" 8.0.0
  (c++)"typeinfo for tinyxml2::XMLDocument@Base" 8.0.0
@@ -202,7 +202,7 @@
  (c++)"typeinfo name for tinyxml2::XMLText@Base" 8.0.0
  (c++)"typeinfo name for tinyxml2::XMLUnknown@Base" 8.0.0
  (c++)"typeinfo name for tinyxml2::XMLVisitor@Base" 8.0.0
- (c++)"vtable for tinyxml2::XMLAttribute@Base" 8.0.0
+#MISSING: 9.0.0+dfsg-3.1# (c++)"vtable for tinyxml2::XMLAttribute@Base" 8.0.0
  (c++)"vtable for tinyxml2::XMLComment@Base" 8.0.0
  (c++)"vtable for tinyxml2::XMLDeclaration@Base" 8.0.0
  (c++)"vtable for tinyxml2::XMLDocument@Base" 8.0.0
dh_makeshlibs: error: failing due to earlier errors
make[1]: *** [debian/rules:15: override_dh_makeshlibs] Error 25
make[1]: Leaving directory '/<<PKGBUILDDIR>>'
make: *** [debian/rules:18: binary] Error 2
dpkg-buildpackage: error: fakeroot debian/rules binary subprocess returned exit status 2