patch, 4 partscontrib/diffall: change comment to reflect actual reason for 'cdup'

diff --git a/contrib/diffall/git-diffall b/contrib/diffall/git-diffall
index 9bbd27f..d706a6d 100755
--- a/contrib/diffall/git-diffall
+++ b/contrib/diffall/git-diffall
@@ -36,7 +36,9 @@ fi
 
 start_dir=$(pwd)
 
-# needed to access tar utility
+# All the file paths returned by the diff command are relative to the root
+# of the working copy. So if the script is called from a subdirectory, it
+# must switch to the root of working copy before trying to use those paths.
 cdup=$(git rev-parse --show-cdup) &&
 cd "$cdup" || {
 	echo >&2 "Cannot chdir to $cdup, the toplevel of the working tree"

diff --git a/contrib/diffall/git-diffall b/contrib/diffall/git-diffall
index d706a6d..443f646 100755
--- a/contrib/diffall/git-diffall
+++ b/contrib/diffall/git-diffall
@@ -45,13 +45,10 @@ cd "$cdup" || {
 	exit 1
 }
 
-# mktemp is not available on all platforms (missing from msysgit)
-# Use a hard-coded tmp dir if it is not available
-tmp="$(mktemp -d -t tmp.XXXXXX 2>/dev/null)" || {
-	tmp=/tmp/git-diffall-tmp.$$
-	mkdir "$tmp" || exit 1
-}
-
+# set up temp dir
+tmp=$(perl -e 'use File::Temp qw(tempdir);
+	$t=tempdir("/tmp/git-diffall.XXXXX") or exit(1);
+	print $t') || exit 1
 trap 'rm -rf "$tmp" 2>/dev/null' EXIT
 
 left=

diff --git a/contrib/diffall/git-diffall b/contrib/diffall/git-diffall
index 443f646..8d243c7 100755
--- a/contrib/diffall/git-diffall
+++ b/contrib/diffall/git-diffall
@@ -202,10 +202,14 @@ then
 		fi
 	done < "$tmp/filelist"
 else
-	# Mac users have gnutar rather than tar
-	(tar --ignore-failed-read -c -T "$tmp/filelist" | (cd "$tmp/$right_dir" && tar -x)) || {
-		gnutar --ignore-failed-read -c -T "$tmp/filelist" | (cd "$tmp/$right_dir" && gnutar -x)
-	}
+	while read name
+	do
+		if test -e "$name"
+		then
+			mkdir -p "$tmp/$right_dir/$(dirname "$name")"
+			cp "$name" "$tmp/$right_dir"
+		fi
+	done < "$tmp/filelist"
 fi
 
 # Populate the tmp/left_dir directory with the files to be compared

diff --git a/contrib/diffall/git-diffall b/contrib/diffall/git-diffall
index 8d243c7..b1afefe 100755
--- a/contrib/diffall/git-diffall
+++ b/contrib/diffall/git-diffall
@@ -179,38 +179,32 @@ fi
 mkdir -p "$tmp/$left_dir" "$tmp/$right_dir"
 
 # Populate the tmp/right_dir directory with the files to be compared
-if test -n "$right"
-then
-	while read name
-	do
+while read name
+do
+	if test -n "$right"
+	then
 		ls_list=$(git ls-tree $right "$name")
 		if test -n "$ls_list"
 		then
 			mkdir -p "$tmp/$right_dir/$(dirname "$name")"
 			git show "$right":"$name" >"$tmp/$right_dir/$name" || true
 		fi
-	done < "$tmp/filelist"
-elif test -n "$compare_staged"
-then
-	while read name
-	do
+	elif test -n "$compare_staged"
+	then
 		ls_list=$(git ls-files -- "$name")
 		if test -n "$ls_list"
 		then
 			mkdir -p "$tmp/$right_dir/$(dirname "$name")"
 			git show :"$name" >"$tmp/$right_dir/$name"
 		fi
-	done < "$tmp/filelist"
-else
-	while read name
-	do
+	else
 		if test -e "$name"
 		then
 			mkdir -p "$tmp/$right_dir/$(dirname "$name")"
 			cp "$name" "$tmp/$right_dir"
 		fi
-	done < "$tmp/filelist"
-fi
+	fi
+done < "$tmp/filelist"
 
 # Populate the tmp/left_dir directory with the files to be compared
 while read name