Include netdb.h to detect getaddrinfo. Work around problem with getaddrinfo

not properly processing numeric IPv4 addresses. Fixes V5.1 part of #472675.

Modules/socketmodule.c

@@ -622,6 +622,12 @@ setipaddr(char* name, struct sockaddr * addr_ret, int af)
 	memset(&hints, 0, sizeof(hints));
 	hints.ai_family = af;
 	error = getaddrinfo(name, NULL, &hints, &res);
+        if (error = EAI_NONAME && af == AF_UNSPEC) {
+          /* On OSF/1 V5.1, numeric-to-addr conversion
+             fails if no address family is given. Assume IPv4 for now.*/
+          hints.ai_family = AF_INET;
+          error = getaddrinfo(name, NULL, &hints, &res);
+        }
 	if (error) {
 		PyGAI_Err(error);
 		return -1;

configure.in

@@ -1426,7 +1426,17 @@ AC_CHECK_FUNCS(getpgrp, AC_TRY_COMPILE([#include <unistd.h>], [getpgrp(0);], AC_
 AC_CHECK_FUNCS(setpgrp, AC_TRY_COMPILE([#include <unistd.h>], [setpgrp(0,0);], AC_DEFINE(SETPGRP_HAVE_ARG)))
 AC_CHECK_FUNCS(gettimeofday, AC_TRY_COMPILE([#include <sys/time.h>], [gettimeofday((struct timeval*)0,(struct timezone*)0);], ,AC_DEFINE(GETTIMEOFDAY_NO_TZ)))
 
-AC_CHECK_FUNCS(getaddrinfo, [dnl
+
+# On OSF/1 V5.1, getaddrinfo is available, but a define
+# for [no]getaddrinfo in netdb.h. 
+AC_MSG_CHECKING(for getaddrinfo)
+AC_TRY_LINK([
+#include <sys/socket.h>
+#include <netdb.h>
+],[
+getaddrinfo(NULL, NULL, NULL, NULL);
+], [
+AC_MSG_RESULT(yes)
 AC_MSG_CHECKING(getaddrinfo bug)
 AC_TRY_RUN([
 #include <sys/types.h>
@@ -1519,7 +1529,10 @@ buggygetaddrinfo=no,
 AC_MSG_RESULT(buggy)
 buggygetaddrinfo=yes,
 AC_MSG_RESULT(buggy)
-buggygetaddrinfo=yes)], [buggygetaddrinfo=yes])
+buggygetaddrinfo=yes)], [
+AC_MSG_RESULT(no)
+buggygetaddrinfo=yes
+])
 
 if test "$buggygetaddrinfo" = "yes"; then
 	if test "$ipv6" = "yes"; then
@@ -1527,6 +1540,8 @@ if test "$buggygetaddrinfo" = "yes"; then
 		echo '       or you can specify "--disable-ipv6"'.
 		exit 1
 	fi
+else
+	AC_DEFINE(HAVE_GETADDRINFO)
 fi
 AC_CHECK_FUNCS(getnameinfo)