$OpenBSD: patch-configure_ac,v 1.18 2021/09/15 08:21:24 sthen Exp $

"struct stat" is in stat.h not fcntl.h
https://gitlab.isc.org/isc-projects/bind9/-/issues/2905

Index: configure.ac
--- configure.ac.orig
+++ configure.ac
@@ -1836,7 +1836,7 @@ AC_DEFINE(NEED_OPTARG, 1, [Defined if extern char *opt
 AC_MSG_CHECKING([for st_mtim.tv_nsec])
 AC_COMPILE_IFELSE(
   [AC_LANG_PROGRAM(
-     [[#include <sys/fcntl.h>]],
+     [[#include <sys/stat.h>]],
      [[struct stat s;
        return(s.st_mtim.tv_nsec);
       ]])],
