https://bz.apache.org/SpamAssassin/show_bug.cgi?id=8073
--- a/spamc/configure.in
+++ b/spamc/configure.in
@@ -48,7 +48,9 @@ dnl ----------------------------------------------------------------------
 AC_CACHE_CHECK([for SHUT_RD],
        shutrd, [
                 AC_TRY_COMPILE([#include <sys/types.h>
-#include <sys/socket.h>],
+#include <sys/socket.h>
+#include <stdio.h>
+],
                         [printf ("%d", SHUT_RD); return 0;],
                                         [shutrd=yes],
                                         [shutrd=no]),
@@ -89,7 +91,8 @@ dnl ----------------------------------------------------------------------
 
 AC_CACHE_CHECK([for h_errno],
         herrno, [
-                AC_TRY_COMPILE([#include <netdb.h>],
+                AC_TRY_COMPILE([#include <netdb.h>
+#include <stdio.h>],
                         [printf ("%d", h_errno); return 0;],
                                         [herrno=yes],
                                         [herrno=no]),
diff --git a/spamc/configure b/spamc/configure
index d8e5dcf..2e30ba4 100755
--- a/spamc/configure
+++ b/spamc/configure
@@ -3555,6 +3555,7 @@ cat >>conftest.$ac_ext <<_ACEOF
 /* end confdefs.h.  */
 #include <sys/types.h>
 #include <sys/socket.h>
+#include <stdio.h>
 int
 main ()
 {
@@ -4253,6 +4254,7 @@ cat confdefs.h >>conftest.$ac_ext
 cat >>conftest.$ac_ext <<_ACEOF
 /* end confdefs.h.  */
 #include <netdb.h>
+#include <stdio.h>
 int
 main ()
 {