https://buildd.debian.org/status/logs.php?pkg=prjxray&ver=0.1%2Bgit3356.gc9f02d85%2B%7Edb20211214.g0a0added-2%2Bb2
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/build/reproducible-path/prjxray-0.1+git3356.gc9f02d85+~db20211214.g0a0added/tools/bittool.cc: In function ‘int ListConfigPackets(int, char**)’:
/build/reproducible-path/prjxray-0.1+git3356.gc9f02d85+~db20211214.g0a0added/tools/bittool.cc:75:27: error: ‘constexpr decltype (std::visit((declval<Args>)()...)) absl::debian10::visit(Args&& ...) [with Args = {ConfigPacketsLister, std::variant<prjxray::xilinx::Series7, prjxray::xilinx::UltraScale, prjxray::xilinx::UltraScalePlus, prjxray::xilinx::Spartan6>&}; decltype (std::visit((declval<Args>)()...)) = int]’ is deprecated [-Werror=deprecated-declarations]
75 | return absl::visit(ConfigPacketsLister(in_bytes), arch_container);
| ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Please remove the -Werror from CMakeLists.txt,
this is too fragile in distribution builds.