Issue #13057: Include stdio.h when NULL is used in configure.ac.
diff --git a/configure b/configure
index 494bef9..40f37de 100755
--- a/configure
+++ b/configure
@@ -5850,6 +5850,7 @@
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
+#include <stdio.h>
 #include <pthread.h>
 
 void* routine(void* p){return NULL;}
@@ -5905,6 +5906,7 @@
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
+#include <stdio.h>
 #include <pthread.h>
 
 void* routine(void* p){return NULL;}
@@ -5954,6 +5956,7 @@
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
+#include <stdio.h>
 #include <pthread.h>
 
 void* routine(void* p){return NULL;}
@@ -6003,6 +6006,7 @@
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
+#include <stdio.h>
 #include <pthread.h>
 
 void* routine(void* p){return NULL;}
@@ -8690,6 +8694,8 @@
 $as_echo_n "checking for pthread_create in -lpthread... " >&6; }
     cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
+
+#include <stdio.h>
 #include <pthread.h>
 
 void * start_routine (void *arg) { exit (0); }
@@ -9082,7 +9088,9 @@
 else
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
-#include <pthread.h>
+
+      #include <stdio.h>
+      #include <pthread.h>
       void *foo(void *parm) {
         return NULL;
       }