DNS Resolve with cutsom dns server

In my app, I want to resolve an address with a DNS server address of my choice (the DNS isn't mine, I just want to resolve domain of my app with other dns server). i have try this code.

 #include <dns.h>
#include <dns_sd.h>
#include <sys/socket.h>

static NSData * synchronousDNSQuery() {
    NSData *                result;
    NSURL *                confURL;
    dns_handle_t            dns;
    uint8_t                responseBuffer[4096];
    struct sockaddr_storage fromAddr;
    uint32_t                fromAddrLen;
    int32_t                queryResult;

    confURL = [[NSBundle mainBundle] URLForResource:@"resolv" withExtension:@"conf"];
    dns = dns_open(confURL.fileSystemRepresentation);

    fromAddrLen = sizeof(fromAddr);
    queryResult = dns_query(
        dns,
        "example.com.",
        kDNSServiceClass_IN,
        kDNSServiceType_A,
        (char *) responseBuffer,
        sizeof(responseBuffer),
        (struct sockaddr *) &fromAddr,
        &fromAddrLen
    );
    if (queryResult > 0) {
        result = [NSData dataWithBytes:responseBuffer length:(NSUInteger) queryResult];
        NSLog(@"response %@ from %@",
            result,
            [NSData dataWithBytes:&fromAddr length:(NSUInteger) fromAddrLen]
        );
    } else {
        result = nil;
        NSLog(@"error");
    }

    dns_free(dns);

    return result;
}

However, this code can not compile success .
here is the error message

Undefined symbols for architecture x86_64
_dns_free
_dns_open
_dns_query

how to resolve this compiler error? or Is there any other way to customize dns service?