gprbuild-2014-3 is not built with $RPM_OPT_FLAGS. 2013-16 did not have this problem, see gcc commands in the build log: https://kojipkgs.fedoraproject.org/packages/gprbuild/2013/16.fc22/data/logs/x86_64/build.log https://kojipkgs.fedoraproject.org/packages/gprbuild/2014/3.fc23/data/logs/x86_64/build.log