configure: fix no default int compile error in ipv6 detection

Closes #12607

diff --git a/configure.ac b/configure.ac
index 3e89da9f328ef9d39d162fcd6735be695186c881..79c98b3c4e9c2e143b5ce44c991c4327055f312c 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -1655,15 +1655,12 @@ AS_HELP_STRING([--disable-ipv6],[Disable IPv6 support]),
 # include <netinet/in6.h>
 #endif
 #endif
-#include <stdlib.h> /* for exit() */
-main()
+
+int main(void)
 {
  struct sockaddr_in6 s;
  (void)s;
- if (socket(AF_INET6, SOCK_STREAM, 0) < 0)
-   exit(1);
- else
-   exit(0);
+ return socket(AF_INET6, SOCK_STREAM, 0) < 0;
 }
 ]])
 ],