Add a test for the dirfd library function (to be used in an upcoming
change).  configure will be regenerated in the next commit.
diff --git a/configure.in b/configure.in
index b7eccb7..fd70d25 100644
--- a/configure.in
+++ b/configure.in
@@ -2562,7 +2562,7 @@
 
 # checks for library functions
 AC_CHECK_FUNCS(alarm accept4 setitimer getitimer bind_textdomain_codeset chown \
- clock confstr ctermid execv faccessat fchmod fchmodat fchown fchownat \
+ clock confstr ctermid dirfd execv faccessat fchmod fchmodat fchown fchownat \
  fexecve fdopendir fork fpathconf fstatat ftime ftruncate futimesat \
  futimens futimes gai_strerror \
  getgrouplist getgroups getlogin getloadavg getpeername getpgid getpid \
diff --git a/pyconfig.h.in b/pyconfig.h.in
index accc893..7f7b3c5 100644
--- a/pyconfig.h.in
+++ b/pyconfig.h.in
@@ -181,6 +181,9 @@
    */
 #undef HAVE_DIRENT_H
 
+/* Define to 1 if you have the `dirfd' function. */
+#undef HAVE_DIRFD
+
 /* Define to 1 if you have the <dlfcn.h> header file. */
 #undef HAVE_DLFCN_H