FTBFS with glibc 2.30

gcc -fPIC -I. -I../../include -DDEBIAN -DHAS_PCRE -DHAS_LDAP -DUSE_LDAP_SASL -DHAS_SQLITE -DMYORIGIN_FROM_FILE -DHAS_CDB -DHAS_LMDB -DHAS_MYSQL -I/usr/include/mysql -DHAS_PGSQL -I/usr/include/postgresql -DHAS_SQLITE -I/usr/include -DHAS_SSL -I/usr/include/openssl -DUSE_SASL_AUTH -I/usr/include/sasl -DUSE_CYRUS_SASL -DUSE_TLS -DHAS_DEV_URANDOM -DDEF_DAEMON_DIR=\"/usr/lib/postfix/sbin\" -DDEF_HTML_DIR=\"/usr/share/doc/postfix/html\" -DDEF_MANPAGE_DIR=\"/usr/share/man\" -DDEF_README_DIR=\"/usr/share/doc/postfix\" -DUSE_DYNAMIC_LIBS -DUSE_DYNAMIC_MAPS -Wmissing-prototypes -Wformat -Wno-comment -fPIC -g -O2 -I. -I../../include -DLINUX4 -c dns_str_resflags.c
dns_str_resflags.c:55:13: warning: RES_AAONLY is deprecated
   55 | "RES_AAONLY", RES_AAONLY,
      | ^~~~~~~~~~~~~~~~~
dns_str_resflags.c:57:13: warning: RES_PRIMARY is deprecated
   57 | "RES_PRIMARY", RES_PRIMARY,
      | ^~~~~~~~~~~~~~~~~~~
dns_str_resflags.c:63:22: error: ‘RES_INSECURE1’ undeclared here (not in a function); did you mean ‘RES_RECURSE’?
   63 | "RES_INSECURE1", RES_INSECURE1,
      | ^~~~~~~~~~~~~
      | RES_RECURSE
dns_str_resflags.c:64:22: error: ‘RES_INSECURE2’ undeclared here (not in a function); did you mean ‘RES_RECURSE’?
   64 | "RES_INSECURE2", RES_INSECURE2,
      | ^~~~~~~~~~~~~
      | RES_RECURSE
dns_str_resflags.c:66:22: error: ‘RES_USE_INET6’ undeclared here (not in a function)
   66 | "RES_USE_INET6", RES_USE_INET6,
      | ^~~~~~~~~~~~~
dns_str_resflags.c:71:13: warning: RES_NOCHECKNAME is deprecated
   71 | "RES_NOCHECKNAME", RES_NOCHECKNAME,
      | ^~~~~~~~~~~~~~~~~~~~~~~~~~~
dns_str_resflags.c:76:13: warning: RES_KEEPTSIG is deprecated
   76 | "RES_KEEPTSIG", RES_KEEPTSIG,
      | ^~~~~~~~~~~~~~~~~~~~~
dns_str_resflags.c:79:13: warning: RES_BLAST is deprecated
   79 | "RES_BLAST", RES_BLAST,
      | ^~~~~~~~~~~~~~~
make: *** [Makefile:85: dns_str_resflags.o] Error 1

Also reported here:
http://postfix.1071664.n5.nabble.com/build-failure-with-glibc-2-30-td102511.html

With fix being in 3.5:
"""
etc. Fixed in Postfix 3.5. You cn delete the offending lines.
"""

I believe I located it in a hunk in this commit:
https://github.com/vdukhovni/postfix/commit/3274c3cea9d739f86e84b65664aabb692e37e83f#diff-777bfb681a1cd539ddc8e1e606959ffa