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/libzen_0.4.39-1_unstable_dpkglto.log
The last lines of the build log are at the end of this report.

[...]
	Be sure to test with dpkg-buildpackage -A/-B as the results may vary when only a subset is built
	If the omission is intentional or no other helper can take care of this consider adding the
	paths to debian/not-installed.

	Remember to be careful with paths containing "x86_64-linux-gnu", where you might need to
	use a wildcard or (assuming compat 13+) e.g. ${DEB_HOST_MULTIARCH} in debian/not-installed
	to ensure it works on all architectures (see #961104).
   dh_dwz
   dh_strip
   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/libzen0v5/DEBIAN/symbols doesn't match completely debian/libzen0v5.symbols
--- debian/libzen0v5.symbols (libzen0v5_0.4.39-1_amd64)
+++ dpkg-gensymbolscgyaLB	2022-06-10 09:06:00.769381536 +0000
@@ -70,7 +70,7 @@
  (c++)"ZenLib::Format::Html::Request::~Request()@Base" 0.4.23
  (c++)"ZenLib::Format::Http::Char2Hex(unsigned char)@Base" 0.4.23
  (c++)"ZenLib::Format::Http::Char2Hex(wchar_t)@Base" 0.4.23
- (optional|c++)"ZenLib::Format::Http::Cookie::~Cookie()@Base" 0.4.23
+#MISSING: 0.4.39-1# (optional|c++)"ZenLib::Format::Http::Cookie::~Cookie()@Base" 0.4.23
  (c++)"ZenLib::Format::Http::Cookies::Cookies()@Base" 0.4.23
  (c++)"ZenLib::Format::Http::Cookies::Create_Lines(std::basic_ostream<char, std::char_traits<char> >&)@Base" 0.4.23
  (c++|regex)"ZenLib::Format::Http::Cookies::Set\(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, long( long)?, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, bool\)@Base" 0.4.31-2~
@@ -227,7 +227,7 @@
  (c++)"ZenLib::Ztring::TrimLeft(wchar_t)@Base" 0.4.23
  (c++)"ZenLib::Ztring::TrimRight(wchar_t)@Base" 0.4.23
  (c++|regex)"ZenLib::Ztring::operator\(\)\(unsigned (int|long)\)@Base" 0.4.23
- (c++)"ZenLib::Ztring::~Ztring()@Base" 0.4.23
+#MISSING: 0.4.39-1# (c++)"ZenLib::Ztring::~Ztring()@Base" 0.4.23
  (c++|regex)"ZenLib::ZtringList::Find\(ZenLib::Ztring const&, unsigned (int|long), ZenLib::Ztring const&, ZenLib::ztring_t\) const@Base" 0.4.23
  (c++)"ZenLib::ZtringList::MaxStringLength_Get()@Base" 0.4.23
  (c++|regex)"ZenLib::ZtringList::Max_Set\(unsigned (int|long), unsigned (int|long)\)@Base" 0.4.23
@@ -249,7 +249,7 @@
  (c++)"ZenLib::ZtringList::operator=(ZenLib::ZtringList const&)@Base" 0.4.23
  (c++)"ZenLib::ZtringList::operator==(ZenLib::ZtringList const&) const@Base" 0.4.23
  (c++|regex)"ZenLib::ZtringList::operator\(\)\(unsigned (int|long)\)@Base" 0.4.23
- (c++)"ZenLib::ZtringList::~ZtringList()@Base" 0.4.23
+#MISSING: 0.4.39-1# (c++)"ZenLib::ZtringList::~ZtringList()@Base" 0.4.23
  (c++|regex)"ZenLib::ZtringListList::Delete1\(unsigned (int|long)\)@Base" 0.4.23
  (c++|regex)"ZenLib::ZtringListList::Delete\(ZenLib::Ztring const&, unsigned (int|long), ZenLib::Ztring const&, ZenLib::ztring_t\)@Base" 0.4.23
  (c++|regex)"ZenLib::ZtringListList::FindValue\(ZenLib::Ztring const&, unsigned (int|long), unsigned (int|long), unsigned (int|long), ZenLib::Ztring const&, ZenLib::ztring_t\) const@Base" 0.4.23
@@ -289,7 +289,7 @@
  (c++|regex)"ZenLib::ZtringListList::operator\(\)\(unsigned (int|long)\)@Base" 0.4.23
  (c++)"ZenLib::ZtringListList::push_back(ZenLib::Ztring const&)@Base" 0.4.23
  (c++)"ZenLib::ZtringListList::push_back(ZenLib::ZtringList const&)@Base" 0.4.23
- (c++)"ZenLib::ZtringListList::~ZtringListList()@Base" 0.4.23
+#MISSING: 0.4.39-1# (c++)"ZenLib::ZtringListList::~ZtringListList()@Base" 0.4.23
  (c++)"ZenLib::ZtringListListF::Backup_Count_Set(unsigned char)@Base" 0.4.23
  (c++)"ZenLib::ZtringListListF::Backup_Set(bool)@Base" 0.4.23
  (c++)"ZenLib::ZtringListListF::CFG_Charger()@Base" 0.4.23
@@ -410,9 +410,9 @@
  (c++)"ZenLib::uint128::uint128(double const&)@Base" 0.4.23
  (c++)"ZenLib::uint128::uint128(float)@Base" 0.4.23
  (c++|regex)"ZenLib::uint128::uint128\((long double|__float128) const&\)@Base" 0.4.23
- (optional|c++|regex)"^(void|ZenLib::ZtringList\*|ZenLib::Ztring\*|bool|wchar_t\*) std::" 0.4.23
- (optional|c++|regex)"^ZenLib::Ztring::ToZtring" 0.4.23
- (optional|c++|regex)"^__gnu_cxx::" 0.4.23
+#MISSING: 0.4.39-1# (optional|c++|regex)"^(void|ZenLib::ZtringList\*|ZenLib::Ztring\*|bool|wchar_t\*) std::" 0.4.23
+#MISSING: 0.4.39-1# (optional|c++|regex)"^ZenLib::Ztring::ToZtring" 0.4.23
+#MISSING: 0.4.39-1# (optional|c++|regex)"^__gnu_cxx::" 0.4.23
  (optional|c++|regex)"^std::" 0.4.23
  (c++)"typeinfo for ZenLib::Thread@Base" 0.4.23
  (c++)"typeinfo name for ZenLib::Thread@Base" 0.4.23
dh_makeshlibs: error: failing due to earlier errors
make[1]: *** [debian/rules:36: override_dh_makeshlibs] Error 25
make[1]: Leaving directory '/<<PKGBUILDDIR>>'
make: *** [debian/rules:39: binary] Error 2
dpkg-buildpackage: error: fakeroot debian/rules binary subprocess returned exit status 2