Fix more usages of NULL without including stdio.h.
diff --git a/configure b/configure
index 534c8df..bea5062 100755
--- a/configure
+++ b/configure
@@ -11620,6 +11620,7 @@
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
+#include <stdio.h>
#include <sys/types.h>
#include <netdb.h>
#include <string.h>
@@ -14833,6 +14834,7 @@
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
+#include <stdio.h>
#include<stdlib.h>
int main() {
size_t len = -1;
diff --git a/configure.ac b/configure.ac
index 862d694..4d4f05f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3119,6 +3119,7 @@
AC_MSG_CHECKING(getaddrinfo bug)
AC_CACHE_VAL(ac_cv_buggy_getaddrinfo,
AC_RUN_IFELSE([AC_LANG_SOURCE([[[
+#include <stdio.h>
#include <sys/types.h>
#include <netdb.h>
#include <string.h>
@@ -4447,6 +4448,7 @@
AC_MSG_CHECKING(for broken mbstowcs)
AC_CACHE_VAL(ac_cv_broken_mbstowcs,
AC_RUN_IFELSE([AC_LANG_SOURCE([[
+#include <stdio.h>
#include<stdlib.h>
int main() {
size_t len = -1;