configure: fix test code to match gethostbyname_r prototype. (#75)

configure: fix test code to match gethostbyname_r prototype. (#75)

This enables the test to work with CC=clang.

Without this the test for 6 args would fail with:

utils.c:99:12: error: static declaration of 'gethostbyname_r' follows non-static declaration
static int gethostbyname_r (const char *name, struct hostent *ret, char *buf,
           ^
/usr/include/netdb.h:177:12: note: previous declaration is here
extern int gethostbyname_r (const char *__restrict __name,
           ^

Fixing the expected return type to int sorts this out.

Signed-off-by: Jaco Kroon <jaco@uls.co.za>