https://bugs.gentoo.org/874759
https://bugs.gentoo.org/883285
https://bugs.gentoo.org/919260
https://src.fedoraproject.org/rpms/udns/c/27e7b66faa416c13b113e895c204373596282c37?branch=rawhide

Provide autoconf-style fake prototype for socket to avoid implicit
function declarations.  Otherwise the check will always fail with soem
C99 compilers.

Avoid incorrect pointer types and a pointer-to-int conversion with
inet_pton and inet_ntop.

--- a/configure
+++ b/configure
@@ -75,6 +75,7 @@ int main(int argc, char **argv) {
 EOF
 
 if ac_library_find_v 'socket and connect' "" "-lsocket -lnsl" <<EOF
+char socket(void); char connect(void);
 int main() { socket(); connect(); return 0; }
 EOF
 then :
@@ -92,8 +93,8 @@ ac_ign \
 int main() {
   char buf[64];
   long x = 0;
-  inet_pton(AF_INET, &x, buf);
-  return inet_ntop(AF_INET, &x, buf, sizeof(buf));
+  inet_pton(AF_INET, (void *) &x, buf);
+  return inet_ntop(AF_INET, (void *) &x, buf, sizeof(buf)) != 0;
 } 
 EOF