Example with gcc:

#include <arpa/nameser.h>

int main(void)
{
    return 0;
}

Compiling with "gcc -ansi test.c" yields

In file included from test.c:1:
/usr/include/arpa/nameser_compat.h:66: error: duplicate member ‘rd’
/usr/include/arpa/nameser_compat.h:67: error: duplicate member ‘tc’
/usr/include/arpa/nameser_compat.h:68: error: duplicate member ‘aa’
/usr/include/arpa/nameser_compat.h:69: error: duplicate member ‘opcode’
/usr/include/arpa/nameser_compat.h:70: error: duplicate member ‘qr’
/usr/include/arpa/nameser_compat.h:72: error: duplicate member ‘rcode’
/usr/include/arpa/nameser_compat.h:73: error: duplicate member ‘cd’
/usr/include/arpa/nameser_compat.h:74: error: duplicate member ‘ad’
/usr/include/arpa/nameser_compat.h:75: error: duplicate member ‘unused’
/usr/include/arpa/nameser_compat.h:76: error: duplicate member ‘ra’
In file included from test.c:2:
/usr/include/arpa/nameser.h:115: error: expected ‘:’, ‘,’, ‘;’, ‘}’ or ‘__attribute__’ before ‘*’ token
/usr/include/arpa/nameser.h:144: error: expected ‘:’, ‘,’, ‘;’, ‘}’ or ‘__attribute__’ before ‘*’ token
/usr/include/arpa/nameser.h:473: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘ns_get16’
/usr/include/arpa/nameser.h:474: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘ns_get32’
/usr/include/arpa/nameser.h:475: error: expected ‘)’ before ‘*’ token
/usr/include/arpa/nameser.h:476: error: expected ‘)’ before ‘*’ token
/usr/include/arpa/nameser.h:477: error: expected ‘;’, ‘,’ or ‘)’ before ‘*’ token
/usr/include/arpa/nameser.h:478: error: expected ‘;’, ‘,’ or ‘)’ before ‘*’ token
/usr/include/arpa/nameser.h:484: error: expected ‘;’, ‘,’ or ‘)’ before ‘*’ token
/usr/include/arpa/nameser.h:488: error: expected ‘)’ before ‘char’
/usr/include/arpa/nameser.h:489: error: expected declaration specifiers or ‘...’ before ‘u_long’
/usr/include/arpa/nameser.h:491: error: expected ‘;’, ‘,’ or ‘)’ before ‘*’ token
/usr/include/arpa/nameser.h:492: error: expected ‘;’, ‘,’ or ‘)’ before ‘*’ token
/usr/include/arpa/nameser.h:493: error: expected declaration specifiers or ‘...’ before ‘u_char’
/usr/include/arpa/nameser.h:494: error: expected ‘;’, ‘,’ or ‘)’ before ‘*’ token
/usr/include/arpa/nameser.h:496: error: expected ‘;’, ‘,’ or ‘)’ before ‘*’ token
/usr/include/arpa/nameser.h:498: error: expected ‘;’, ‘,’ or ‘)’ before ‘*’ token
/usr/include/arpa/nameser.h:500: error: expected declaration specifiers or ‘...’ before ‘u_char’
/usr/include/arpa/nameser.h:501: error: expected ‘;’, ‘,’ or ‘)’ before ‘*’ token
/usr/include/arpa/nameser.h:502: error: expected ‘;’, ‘,’ or ‘)’ before ‘*’ token
/usr/include/arpa/nameser.h:503: error: expected ‘;’, ‘,’ or ‘)’ before ‘*’ token
/usr/include/arpa/nameser.h:505: error: expected ‘)’ before ‘*’ token
/usr/include/arpa/nameser.h:507: error: expected ‘)’ before ‘*’ token
/usr/include/arpa/nameser.h:510: error: expected ‘)’ before ‘*’ token
/usr/include/arpa/nameser.h:512: error: expected ‘)’ before ‘*’ token
/usr/include/arpa/nameser.h:515: error: expected ‘;’, ‘,’ or ‘)’ before ‘*’ token
/usr/include/arpa/nameser.h:517: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘*’ token
/usr/include/arpa/nameser.h:518: error: expected ‘)’ before ‘*’ token
/usr/include/arpa/nameser.h:520: error: expected ‘)’ before ‘*’ token
/usr/include/arpa/nameser.h:522: error: expected ‘;’, ‘,’ or ‘)’ before ‘*’ token