The main executables in jbigkit-2.1-11.fc28.x86_64 (/usr/bin/jbgtopbm etc.) and /usr/lib64/libjbig.so.2.1, /usr/lib64/libjbig85.so.2.1 in jbigkit-libs-2.1-11.fc28.x86_64 are not linked with the standard Fedora linker flags (LDFLAGS) from redhat-rpm-config. It looks like the package makefiles do not use LDFLAGS at all. See https://src.fedoraproject.org/rpms/redhat-rpm-config/blob/master/f/buildflags.md for information on RPM macros and environment variables provided by the build environment.
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