/usr/lib64/libkpathsea.so.6.2.2, /usr/lib64/libptexenc.so.1.3.4, /usr/lib64/libsynctex.so.1.18.0, /usr/lib64/libtexlua52.so.5.2.4, /usr/lib64/libtexluajit.so.2.1.0 in texlive-lib-6:2016-41.20160520.fc28.x86_64 are not linked with the standard Fedora linker flags (LDFLAGS) from redhat-rpm-config.

The first linker invocation looks like this:

libtool: link: gcc -shared  -fPIC -DPIC  .libs/libkpathsea_la-tex-file.o .libs/libkpathsea_la-absolute.o .libs/libkpathsea_la-atou.o .libs/libkpathsea_la-cnf.o .libs/libkpathsea_la-concat.o .libs/libkpathsea_la-concat3.o .libs/libkpathsea_la-concatn.o .libs/libkpathsea_la-db.o .libs/libkpathsea_la-debug.o .libs/libkpathsea_la-dir.o .libs/libkpathsea_la-elt-dirs.o .libs/libkpathsea_la-expand.o .libs/libkpathsea_la-extend-fname.o .libs/libkpathsea_la-file-p.o .libs/libkpathsea_la-find-suffix.o .libs/libkpathsea_la-fn.o .libs/libkpathsea_la-fontmap.o .libs/libkpathsea_la-hash.o .libs/libkpathsea_la-kdefault.o .libs/libkpathsea_la-kpathsea.o .libs/libkpathsea_la-line.o .libs/libkpathsea_la-magstep.o .libs/libkpathsea_la-make-suffix.o .libs/libkpathsea_la-path-elt.o .libs/libkpathsea_la-pathsearch.o .libs/libkpathsea_la-proginit.o .libs/libkpathsea_la-progname.o .libs/libkpathsea_la-readable.o .libs/libkpathsea_la-rm-suffix.o .libs/libkpathsea_la-str-list.o .libs/libkpathsea_la-str-llist.o .libs/libkpathsea_la-tex-glyph.o .libs/libkpathsea_la-tex-hush.o .libs/libkpathsea_la-tex-make.o .libs/libkpathsea_la-tilde.o .libs/libkpathsea_la-uppercasify.o .libs/libkpathsea_la-variable.o .libs/libkpathsea_la-version.o .libs/libkpathsea_la-xbasename.o .libs/libkpathsea_la-xcalloc.o .libs/libkpathsea_la-xdirname.o .libs/libkpathsea_la-xfopen.o .libs/libkpathsea_la-xfseek.o .libs/libkpathsea_la-xftell.o .libs/libkpathsea_la-xgetcwd.o .libs/libkpathsea_la-xmalloc.o .libs/libkpathsea_la-xopendir.o .libs/libkpathsea_la-xputenv.o .libs/libkpathsea_la-xrealloc.o .libs/libkpathsea_la-xstat.o .libs/libkpathsea_la-xstrdup.o .libs/libkpathsea_la-getopt.o .libs/libkpathsea_la-getopt1.o .libs/libkpathsea_la-xfseeko.o .libs/libkpathsea_la-xftello.o    -O2 -g -fstack-protector-strong -grecord-gcc-switches -m64 -mtune=generic -mcet -Wl,-z -Wl,relro   -Wl,-soname -Wl,libkpathsea.so.6 -o .libs/libkpathsea.so.6.2.2

It appears that something dropped the -specs=/usr/lib/rpm/redhat/redhat-hardened-ld argument.

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.