It fails in all Fedoras.

g++ -I.. -O2 -g -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions -fstack-protector-strong -grecord-gcc-switches -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -mcet -fcf-protection -o test_kdtree test_kdtree.cpp
In file included from test_kdtree.cpp:6:
../kdtree++/kdtree.hpp: In function 'std::ostream& KDTree::operator<<(std::ostream&, const KDTree::KDTree<__K, _Val, _Acc, _Dist, _Cmp, _Alloc>&)':
../kdtree++/kdtree.hpp:1200:28: error: no match for 'operator<<' (operand types are 'std::basic_ostream<char>' and 'const KDTree::_Node_base')
       o << "meta node:   " << tree._M_header << std::endl;
       ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~

Additional information:
https://apps.fedoraproject.org/koschei/package/libkdtree++

Created attachment 1443192 [details]
build.log

Created attachment 1443193 [details]
root.log

Created attachment 1443194 [details]
state.log

Dear Maintainer,

your package has not been built successfully in F28. Action is required from you.

If you can fix your package to build, perform a build in koji, and either create
an update in bodhi, or close this bug without creating an update, if updating is
not appropriate [1]. If you are working on a fix, set the status to ASSIGNED to
acknowledge this. Following the latest policy for such packages [2], your package
will be orphaned if this bug remains in NEW state more than 8 weeks.

[1] https://fedoraproject.org/wiki/Updates_Policy
[2] https://fedoraproject.org/wiki/Fails_to_build_from_source#Package_Removal_for_Long-standing_FTBFS_bugs

Dear Maintainer,

your package has not been built successfully in F28. Action is required from you.

If you can fix your package to build, perform a build in koji, and either create
an update in bodhi, or close this bug without creating an update, if updating is
not appropriate [1]. If you are working on a fix, set the status to ASSIGNED to acknowledge this. Following the latest policy for such packages [2], your package will be orphaned if this bug remains in NEW state more than 8 weeks.

[1] https://fedoraproject.org/wiki/Updates_Policy
[2] https://fedoraproject.org/wiki/Fails_to_build_from_source#Package_Removal_for_Long-standing_FTBFS_bugs

*** Bug 1604605 has been marked as a duplicate of this bug. ***

*** Bug 1675285 has been marked as a duplicate of this bug. ***

Let's orphan it.

libkdtree++-0.7.0-21.fc30 has been submitted as an update to Fedora 30. https://bodhi.fedoraproject.org/updates/FEDORA-2019-30a56d7fda

libkdtree++-0.7.0-21.fc30 has been pushed to the Fedora 30 testing repository. If problems still persist, please make note of it in this bug report.
See https://fedoraproject.org/wiki/QA:Updates_Testing for
instructions on how to install test updates.
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2019-30a56d7fda

libkdtree++-0.7.0-21.fc30 has been pushed to the Fedora 30 stable repository. If problems still persist, please make note of it in this bug report.