sldns_b64_contains_nonurl
if(sldns_b64_contains_nonurl((char const*)start, length)) {
int sldns_b64_contains_nonurl(char const *src, size_t srcsize);
if(sldns_b64_contains_nonurl((char const*)start, length)) {
int sldns_b64_contains_nonurl(char const *src, size_t srcsize);