--- a/build-aux/install-sh
+++ b/build-aux/install-sh
@@ -1,7 +1,7 @@
 #!/bin/sh
 # install - install a program, script, or datafile
 
-scriptversion=2013-10-30.23; # UTC
+scriptversion=2013-12-25.23; # UTC
 
 # This originates from X11R5 (mit/util/scripts/install.sh), which was
 # later released in X11R6 (xc/config/util/install.sh) with the
@@ -82,7 +82,7 @@
 dst_arg=
 
 copy_on_change=false
-no_target_directory=
+is_target_a_directory=possibly
 
 usage="\
 Usage: $0 [OPTION]... [-T] SRCFILE DSTFILE
@@ -139,14 +139,16 @@
 
     -s) stripcmd=$stripprog;;
 
-    -t) dst_arg=$2
+    -t)
+        is_target_a_directory=always
+        dst_arg=$2
         # Protect names problematic for 'test' and other utilities.
         case $dst_arg in
           -* | [=\(\)!]) dst_arg=./$dst_arg;;
         esac
         shift;;
 
-    -T) no_target_directory=true;;
+    -T) is_target_a_directory=never;;
 
     --version) echo "$0 $scriptversion"; exit $?;;
 
@@ -161,6 +163,16 @@
   shift
 done
 
+# We allow the use of options -d and -T together, by making -d
+# take the precedence; this is for compatibility with GNU install.
+
+if test -n "$dir_arg"; then
+  if test -n "$dst_arg"; then
+    echo "$0: target directory not allowed when installing a directory." >&2
+    exit 1
+  fi
+fi
+
 if test $# -ne 0 && test -z "$dir_arg$dst_arg"; then
   # When -d is used, all remaining arguments are directories to create.
   # When -t is used, the destination is already specified.
@@ -192,6 +204,15 @@
 fi
 
 if test -z "$dir_arg"; then
+  if test $# -gt 1 || test "$is_target_a_directory" = always; then
+    if test ! -d "$dst_arg"; then
+      echo "$0: $dst_arg: Is not a directory." >&2
+      exit 1
+    fi
+  fi
+fi
+
+if test -z "$dir_arg"; then
   do_exit='(exit $ret); exit $ret'
   trap "ret=129; $do_exit" 1
   trap "ret=130; $do_exit" 2
@@ -253,7 +274,7 @@
     # If destination is a directory, append the input filename; won't work
     # if double slashes aren't ignored.
     if test -d "$dst"; then
-      if test -n "$no_target_directory"; then
+      if test "$is_target_a_directory" = never; then
         echo "$0: $dst_arg: Is a directory" >&2
         exit 1
       fi