moarvm 0.2017.04-1 is apparently not built with $RPM_OPT_FLAGS. It's a bit hard to tell for sure, because the build is so non-verbose, but the usual symtom of faulty debuginfo is present, and the compiler command lines presented during build don't have the desired flags. 0.2017.01-1 did not have this problem.
rakudo-0.2017.04.2-2.fc26 nqp-0.0.2017.04-2.fc26 moarvm-0.2017.04-2.fc26 has been submitted as an update to Fedora 26. https://bodhi.fedoraproject.org/updates/FEDORA-2017-750d8d878d
In the rebuild $RPM_OPT_FLAGS is added again to the cflags.
moarvm-0.2017.04-2.fc26, nqp-0.0.2017.04-2.fc26, rakudo-0.2017.04.2-2.fc26 has been pushed to the Fedora 26 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-2017-750d8d878d
moarvm-0.2017.04-2.fc26, nqp-0.0.2017.04-2.fc26, rakudo-0.2017.04.2-2.fc26 has been pushed to the Fedora 26 stable repository. If problems still persist, please make note of it in this bug report.