diff --git a/Configure b/Configure
index 44c12ced40..7a13249caa 100755
--- a/Configure
+++ b/Configure
@@ -478,6 +478,7 @@ d_fd_set=''
 d_fds_bits=''
 d_fdclose=''
 d_fdim=''
+d_fdopendir=''
 d_fegetround=''
 d_ffs=''
 d_ffsl=''
@@ -13344,6 +13345,10 @@ esac
 set i_fcntl
 eval $setvar
 
+: see if fdopendir exists
+set fdopendir d_fdopendir
+eval $inlibc
+
 : see if fork exists
 set fork d_fork
 eval $inlibc
@@ -25052,6 +25057,7 @@ d_flockproto='$d_flockproto'
 d_fma='$d_fma'
 d_fmax='$d_fmax'
 d_fmin='$d_fmin'
+d_fdopendir='$d_fdopendir'
 d_fork='$d_fork'
 d_fp_class='$d_fp_class'
 d_fp_classify='$d_fp_classify'
diff --git a/Cross/config.sh-arm-linux b/Cross/config.sh-arm-linux
index bfa0b00d5f..9e05653919 100644
--- a/Cross/config.sh-arm-linux
+++ b/Cross/config.sh-arm-linux
@@ -212,6 +212,7 @@ d_fd_macros='define'
 d_fd_set='define'
 d_fdclose='undef'
 d_fdim='undef'
+d_fdopendir=undef
 d_fds_bits='undef'
 d_fegetround='define'
 d_ffs='undef'
diff --git a/Cross/config.sh-arm-linux-n770 b/Cross/config.sh-arm-linux-n770
index 47ad5c37e3..365e4c4f96 100644
--- a/Cross/config.sh-arm-linux-n770
+++ b/Cross/config.sh-arm-linux-n770
@@ -211,6 +211,7 @@ d_fd_macros='define'
 d_fd_set='define'
 d_fdclose='undef'
 d_fdim='undef'
+d_fdopendir=undef
 d_fds_bits='undef'
 d_fegetround='define'
 d_ffs='undef'
diff --git a/Porting/Glossary b/Porting/Glossary
index bb505c653b..8b2965ca99 100644
--- a/Porting/Glossary
+++ b/Porting/Glossary
@@ -947,6 +947,11 @@ d_fmin (d_fmin.U):
 	This variable conditionally defines the HAS_FMIN symbol, which
 	indicates to the C program that the fmin() routine is available.
 
+d_fdopendir (d_fdopendir.U):
+	This variable conditionally defines the HAS_FORK symbol, which
+	indicates that the fdopen routine is available to open a
+	directory descriptor.
+
 d_fork (d_fork.U):
 	This variable conditionally defines the HAS_FORK symbol, which
 	indicates to the C program that the fork() routine is available.
diff --git a/Porting/config.sh b/Porting/config.sh
index a921f7e1c7..6231ea0f31 100644
--- a/Porting/config.sh
+++ b/Porting/config.sh
@@ -223,6 +223,7 @@ d_fd_macros='define'
 d_fd_set='define'
 d_fdclose='undef'
 d_fdim='define'
+d_fdopendir='define'
 d_fds_bits='define'
 d_fegetround='define'
 d_ffs='define'
diff --git a/config_h.SH b/config_h.SH
index da0f2dbcd7..5a0f81cf20 100755
--- a/config_h.SH
+++ b/config_h.SH
@@ -142,6 +142,12 @@ sed <<!GROK!THIS! >$CONFIG_H -e 's!^#undef\(.*/\)\*!/\*#define\1 \*!' -e 's!^#un
  */
 #$d_fcntl HAS_FCNTL		/**/
 
+/* HAS_FDOPENDIR:
+ * This symbol, if defined, indicates that the fdopen routine is
+ * available to open a directory descriptor.
+ */
+#$d_fdopendir HAS_FDOPENDIR		/**/
+
 /* HAS_FGETPOS:
  *	This symbol, if defined, indicates that the fgetpos routine is
  *	available to get the file position indicator, similar to ftell().
diff --git a/configure.com b/configure.com
index 99527c180b..7c38711bb8 100644
--- a/configure.com
+++ b/configure.com
@@ -6010,6 +6010,7 @@ $ WC "d_fd_set='" + d_fd_set + "'"
 $ WC "d_fd_macros='define'"
 $ WC "d_fdclose='undef'"
 $ WC "d_fdim='" + d_fdim + "'"
+$ WC "d_fdopendir='undef'"
 $ WC "d_fds_bits='define'"
 $ WC "d_fegetround='undef'"
 $ WC "d_ffs='undef'"
diff --git a/plan9/config_sh.sample b/plan9/config_sh.sample
index 636acbdf6d..246bad9544 100644
--- a/plan9/config_sh.sample
+++ b/plan9/config_sh.sample
@@ -212,6 +212,7 @@ d_fd_macros='undef'
 d_fd_set='undef'
 d_fdclose='undef'
 d_fdim='undef'
+d_fdopendir=undef
 d_fds_bits='undef'
 d_fegetround='undef'
 d_ffs='undef'
diff --git a/win32/config.gc b/win32/config.gc
index f8776188c0..34aa8de6ed 100644
--- a/win32/config.gc
+++ b/win32/config.gc
@@ -199,6 +199,7 @@ d_fd_macros='define'
 d_fd_set='define'
 d_fdclose='undef'
 d_fdim='undef'
+d_fdopendir='undef'
 d_fds_bits='define'
 d_fegetround='undef'
 d_ffs='undef'
diff --git a/win32/config.vc b/win32/config.vc
index 619979e22b..536085fe94 100644
--- a/win32/config.vc
+++ b/win32/config.vc
@@ -199,6 +199,7 @@ d_fd_macros='define'
 d_fd_set='define'
 d_fdclose='undef'
 d_fdim='undef'
+d_fdopendir='undef'
 d_fds_bits='define'
 d_fegetround='undef'
 d_ffs='undef'