glibc-2.30 removed RES_INSECURE1, RES_INSECURE2 and RES_USE_INET6 symbols[1] resulting in:
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, | ^~~~~~~~~~~~~~~ FYI -- Eray [1] https://sourceware.org/ml/libc-alpha/2019-08/msg00029.html