Fix org#2666 About fixing getaddrinfo check in ./configure

Thanks to Florian Weimer

The exit function is not declared in this context, so the check will always
fail with compilers which do not accept implicit function declarations. Change
the return type of main to int and return directly from main instead.

bacula/autoconf/configure.in

@@ -2586,7 +2586,7 @@ AC_CACHE_CHECK(for working getaddrinfo, ac_cv_working_getaddrinfo,
 	      #include <sys/types.h>
 	      #include <sys/socket.h>
 
-	      void main(void) {
+	      int main(void) {
 		  struct addrinfo hints, *ai;
 		  int error;
 
@@ -2595,12 +2595,12 @@ AC_CACHE_CHECK(for working getaddrinfo, ac_cv_working_getaddrinfo,
 		  hints.ai_socktype = SOCK_STREAM;
 		  error = getaddrinfo("127.0.0.1", NULL, &hints, &ai);
 		  if (error) {
-		      exit(1);
+		      return(1);
 		  }
 		  if (ai->ai_addr->sa_family != AF_INET) {
-		      exit(1);
+		      return(1);
 		  }
-		  exit(0);
+		  return(0);
 	      }
 	  ],[
 	      ac_cv_working_getaddrinfo="yes"