diff --git a/install-sh b/install-sh
index e9de238..0ec27bc 100755
--- a/install-sh
+++ b/install-sh
@@ -1,19 +1,37 @@
 #!/bin/sh
 #
 # install - install a program, script, or datafile
-# This comes from X11R5 (mit/util/scripts/install.sh).
 #
-# Copyright 1991 by the Massachusetts Institute of Technology
+# This originates from X11R5 (mit/util/scripts/install.sh), which was
+# later released in X11R6 (xc/config/util/install.sh) with the
+# following copyright and license.
 #
-# Permission to use, copy, modify, distribute, and sell this software and its
-# documentation for any purpose is hereby granted without fee, provided that
-# the above copyright notice appear in all copies and that both that
-# copyright notice and this permission notice appear in supporting
-# documentation, and that the name of M.I.T. not be used in advertising or
-# publicity pertaining to distribution of the software without specific,
-# written prior permission.  M.I.T. makes no representations about the
-# suitability of this software for any purpose.  It is provided "as is"
-# without express or implied warranty.
+# Copyright (C) 1994 X Consortium
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to
+# deal in the Software without restriction, including without limitation the
+# rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+# sell copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+# X CONSORTIUM BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+# AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNEC-
+# TION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+#
+# Except as contained in this notice, the name of the X Consortium shall not
+# be used in advertising or otherwise to promote the sale, use or other deal-
+# ings in this Software without prior written authorization from the X Consor-
+# tium.
+#
+#
+# FSF changes to this file are in the public domain.
 #
 # Calling this script install-sh is preferred over install.sh, to prevent
 # `make' implicit rules from creating a file called install from it
@@ -56,7 +74,7 @@
 
 while [ x"$1" != x ]; do
     case $1 in
-	-c) instcmd="$cpprog"
+	-c) instcmd=$cpprog
 	    shift
 	    continue;;
 
@@ -79,7 +97,7 @@
 	    shift
 	    continue;;
 
-	-s) stripcmd="$stripprog"
+	-s) stripcmd=$stripprog
 	    shift
 	    continue;;
 
@@ -106,128 +124,132 @@
 
 if [ x"$src" = x ]
 then
-	echo "install:	no input file specified"
+	echo "$0: no input file specified" >&2
 	exit 1
 else
-	true
+	:
 fi
 
 if [ x"$dir_arg" != x ]; then
 	dst=$src
 	src=""
-	
-	if [ -d $dst ]; then
+
+	if [ -d "$dst" ]; then
 		instcmd=:
 		chmodcmd=""
 	else
-		instcmd=mkdir
+		instcmd=$mkdirprog
 	fi
 else
 
 # Waiting for this to be detected by the "$instcmd $src $dsttmp" command
-# might cause directories to be created, which would be especially bad 
+# might cause directories to be created, which would be especially bad
 # if $src (and thus $dsttmp) contains '*'.
 
-	if [ -f $src -o -d $src ]
+	if [ -f "$src" ] || [ -d "$src" ]
 	then
-		true
+		:
 	else
-		echo "install:  $src does not exist"
+		echo "$0: $src does not exist" >&2
 		exit 1
 	fi
-	
+
 	if [ x"$dst" = x ]
 	then
-		echo "install:	no destination specified"
+		echo "$0: no destination specified" >&2
 		exit 1
 	else
-		true
+		:
 	fi
 
 # If destination is a directory, append the input filename; if your system
 # does not like double slashes in filenames, you may need to add some logic
 
-	if [ -d $dst ]
+	if [ -d "$dst" ]
 	then
-		dst="$dst"/`basename $src`
+		dst=$dst/`basename "$src"`
 	else
-		true
+		:
 	fi
 fi
 
 ## this sed command emulates the dirname command
-dstdir=`echo $dst | sed -e 's,[^/]*$,,;s,/$,,;s,^$,.,'`
+dstdir=`echo "$dst" | sed -e 's,[^/]*$,,;s,/$,,;s,^$,.,'`
 
 # Make sure that the destination directory exists.
 #  this part is taken from Noah Friedman's mkinstalldirs script
 
 # Skip lots of stat calls in the usual case.
 if [ ! -d "$dstdir" ]; then
-defaultIFS='	
-'
-IFS="${IFS-${defaultIFS}}"
+defaultIFS='
+	'
+IFS="${IFS-$defaultIFS}"
 
-oIFS="${IFS}"
+oIFS=$IFS
 # Some sh's can't handle IFS=/ for some reason.
 IFS='%'
-set - `echo ${dstdir} | sed -e 's@/@%@g' -e 's@^%@/@'`
-IFS="${oIFS}"
+set - `echo "$dstdir" | sed -e 's@/@%@g' -e 's@^%@/@'`
+IFS=$oIFS
 
 pathcomp=''
 
 while [ $# -ne 0 ] ; do
-	pathcomp="${pathcomp}${1}"
+	pathcomp=$pathcomp$1
 	shift
 
-	if [ ! -d "${pathcomp}" ] ;
+	if [ ! -d "$pathcomp" ] ;
         then
-		$mkdirprog "${pathcomp}"
+		$mkdirprog "$pathcomp"
 	else
-		true
+		:
 	fi
 
-	pathcomp="${pathcomp}/"
+	pathcomp=$pathcomp/
 done
 fi
 
 if [ x"$dir_arg" != x ]
 then
-	$doit $instcmd $dst &&
+	$doit $instcmd "$dst" &&
 
-	if [ x"$chowncmd" != x ]; then $doit $chowncmd $dst; else true ; fi &&
-	if [ x"$chgrpcmd" != x ]; then $doit $chgrpcmd $dst; else true ; fi &&
-	if [ x"$stripcmd" != x ]; then $doit $stripcmd $dst; else true ; fi &&
-	if [ x"$chmodcmd" != x ]; then $doit $chmodcmd $dst; else true ; fi
+	if [ x"$chowncmd" != x ]; then $doit $chowncmd "$dst"; else : ; fi &&
+	if [ x"$chgrpcmd" != x ]; then $doit $chgrpcmd "$dst"; else : ; fi &&
+	if [ x"$stripcmd" != x ]; then $doit $stripcmd "$dst"; else : ; fi &&
+	if [ x"$chmodcmd" != x ]; then $doit $chmodcmd "$dst"; else : ; fi
 else
 
 # If we're going to rename the final executable, determine the name now.
 
-	if [ x"$transformarg" = x ] 
+	if [ x"$transformarg" = x ]
 	then
-		dstfile=`basename $dst`
+		dstfile=`basename "$dst"`
 	else
-		dstfile=`basename $dst $transformbasename | 
+		dstfile=`basename "$dst" $transformbasename |
 			sed $transformarg`$transformbasename
 	fi
 
 # don't allow the sed command to completely eliminate the filename
 
-	if [ x"$dstfile" = x ] 
+	if [ x"$dstfile" = x ]
 	then
-		dstfile=`basename $dst`
+		dstfile=`basename "$dst"`
 	else
-		true
+		:
 	fi
 
-# Make a temp file name in the proper directory.
+# Make a couple of temp file names in the proper directory.
 
 	dsttmp=$dstdir/#inst.$$#
+	rmtmp=$dstdir/#rm.$$#
+
+# Trap to clean up temp files at exit.
+
+	trap 'status=$?; rm -f "$dsttmp" "$rmtmp" && exit $status' 0
+	trap '(exit $?); exit' 1 2 13 15
 
 # Move or copy the file name to the temp name
 
-	$doit $instcmd $src $dsttmp &&
-
-	trap "rm -f ${dsttmp}" 0 &&
+	$doit $instcmd "$src" "$dsttmp" &&
 
 # and set any options; do chmod last to preserve setuid bits
 
@@ -235,17 +257,38 @@
 # ignore errors from any of these, just make sure not to ignore
 # errors from the above "$doit $instcmd $src $dsttmp" command.
 
-	if [ x"$chowncmd" != x ]; then $doit $chowncmd $dsttmp; else true;fi &&
-	if [ x"$chgrpcmd" != x ]; then $doit $chgrpcmd $dsttmp; else true;fi &&
-	if [ x"$stripcmd" != x ]; then $doit $stripcmd $dsttmp; else true;fi &&
-	if [ x"$chmodcmd" != x ]; then $doit $chmodcmd $dsttmp; else true;fi &&
+	if [ x"$chowncmd" != x ]; then $doit $chowncmd "$dsttmp"; else :;fi &&
+	if [ x"$chgrpcmd" != x ]; then $doit $chgrpcmd "$dsttmp"; else :;fi &&
+	if [ x"$stripcmd" != x ]; then $doit $stripcmd "$dsttmp"; else :;fi &&
+	if [ x"$chmodcmd" != x ]; then $doit $chmodcmd "$dsttmp"; else :;fi &&
+
+# Now remove or move aside any old file at destination location.  We try this
+# two ways since rm can't unlink itself on some systems and the destination
+# file might be busy for other reasons.  In this case, the final cleanup
+# might fail but the new file should still install successfully.
+
+{
+	if [ -f "$dstdir/$dstfile" ]
+	then
+		$doit $rmcmd -f "$dstdir/$dstfile" 2>/dev/null ||
+		$doit $mvcmd -f "$dstdir/$dstfile" "$rmtmp" 2>/dev/null ||
+		{
+		  echo "$0: cannot unlink or rename $dstdir/$dstfile" >&2
+		  (exit 1); exit
+		}
+	else
+		:
+	fi
+} &&
 
 # Now rename the file to the real destination.
 
-	$doit $rmcmd -f $dstdir/$dstfile &&
-	$doit $mvcmd $dsttmp $dstdir/$dstfile 
+	$doit $mvcmd "$dsttmp" "$dstdir/$dstfile"
 
 fi &&
 
+# The final little trick to "correctly" pass the exit status to the exit trap.
 
-exit 0
+{
+	(exit 0); exit
+}