With libunwind-devel installed (so mesa's optional libunwind support is used), build fails with an error similar to described in https://patchwork.ozlabs.org/patch/777332/ which references http://patchwork.ozlabs.org/patch/783462/ that implies it is a libunwind bug.
libunwind-1.2.1-2.fc27 has been submitted as an update to Fedora 27. https://bodhi.fedoraproject.org/updates/FEDORA-2017-b29d12f72b
libunwind-1.2.1-2.fc27 has been pushed to the Fedora 27 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-2017-b29d12f72b
libunwind-1.2.1-2.fc27 has been pushed to the Fedora 27 stable repository. If problems still persist, please make note of it in this bug report.