dns_txt.c:(.text+0x35): undefined reference to `__res_query'

qmail 설치시 에러 발생

gcc -DBIND_8_COMPAT -O2 -o dktest dktest.o -L. -ldomainkeys -lcrypto `cat dns.lib`
./libdomainkeys.a(dns_txt.o): In function `dns_text':
dns_txt.c:(.text+0x35): undefined reference to `__res_query'
dns_txt.c:(.text+0xcf): undefined reference to `__dn_expand'
dns_txt.c:(.text+0x147): undefined reference to `__dn_expand'
collect2: ld returned 1 exit status
해결
yum install bind-libs