Some host tools don't build with glibc 2.28
Username: K900
Origin: https://bugs.openwrt.org/index.php?do=details&task_id=1753
Notably m4 and findutils. The relevant gnulib commit
http://git.savannah.gnu.org/gitweb/?p=gnulib.git;a=commit;h=4af4a4a71827c0bc5e0ec67af23edef4f15cee8e
needs to be applied to the vendored gnulib bits in both packages.