diff --git a/configure b/configure
index 5e627668420..a1caaa49c10 100755
--- a/configure
+++ b/configure
@@ -5935,7 +5935,6 @@ for ac_header in \
 	sys/timeout.h \
 	sys/times.h \
 	sys/uio.h \
-	sys/un.h \
 	sys/utsname.h \
 	sys/vm86.h \
 	sys/wait.h \
@@ -6036,6 +6035,7 @@ for ac_header in \
 	netinet/ip_var.h \
 	netinet/udp.h \
 	netipx/ipx.h \
+	sys/un.h \
 
 do :
   as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
diff --git a/configure.ac b/configure.ac
index 372bc06caf0..d14a2df2a81 100644
--- a/configure.ac
+++ b/configure.ac
@@ -522,7 +522,6 @@ AC_CHECK_HEADERS(\
 	sys/timeout.h \
 	sys/times.h \
 	sys/uio.h \
-	sys/un.h \
 	sys/utsname.h \
 	sys/vm86.h \
 	sys/wait.h \
@@ -559,6 +558,7 @@ AC_CHECK_HEADERS(\
 	netinet/ip_var.h \
 	netinet/udp.h \
 	netipx/ipx.h \
+	sys/un.h \
 ,,,[#include <sys/types.h>
      #ifdef HAVE_SYS_SOCKET_H
      # include <sys/socket.h>