--- /dev/null
+#!/bin/sh
+# Take a list of MSYS-compatible paths and convert them to native
+# MS-Windows format.
+# Status is zero if successful, nonzero otherwise.
+
+# Copyright (C) 2013 Free Software Foundation, Inc.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+# Take only the basename from the full pathname
+me=${0//*\//}
+
+usage="usage: ${me} PATHLIST [MUSTEXIST] [SEPARATOR [SEPARATOR2]]"
+
+help="$usage
+ or: ${me} OPTION
+
+Convert MSYS-compatible paths to MS-Windows native format.
+
+PATHLIST should be a list of paths separated by SEPARATOR. This list
+will be written to the standard output after performing the following
+transformations:
+1. Discard empty paths.
+2. Replace backslashes with forward slashes.
+3. Replace two consecutive slashes with single ones.
+4. Translate to Windows-native format those paths that are not in such
+ format already. The translated paths will not end with a slash,
+ except for root directories (e.g. 'c:/' or 'c:/foo').
+5. Escape with backslashes every ocurrence of SEPARATOR2 within the paths.
+6. Concatenate the translated paths with SEPARATOR2.
+
+If MUSTEXIST is 'Y' or not supplied, then each path in PATHLIST must
+exist. Otherwise, only some part of each path is required to exist
+(the deepest existing subpath will be translated and the remainder
+concatenated to the translation).
+
+If SEPARATOR is not supplied, PATHLIST will be regarded as a single
+path.
+
+If SEPARATOR2 is not supplied, it will take the same value as
+SEPARATOR.
+
+Options:
+ --help display this help and exit
+
+Report bugs to <bug-gnu-emacs@gnu.org>."
+
+for arg
+do
+ case $arg in
+ --help | --hel | --he | --h)
+ exec echo "$help" ;;
+ --)
+ shift
+ break ;;
+ -*)
+ echo "${me}: invalid option: $arg" >&2
+ exit 1 ;;
+ *)
+ break ;;
+ esac
+done
+
+{ test $# -ge 1 && test $# -le 4; } ||
+{ echo "${me}: $usage" >&2; exit 1; }
+
+# Arguments
+pathlist="$1"
+mustexist="${2:-Y}"
+separator="$3"
+separator2="${4:-${separator}}"
+
+# Split pathlist into its path components
+if test -n "$separator"
+then
+ IFS=${separator} patharray=( $pathlist )
+else
+ patharray=( "$pathlist" )
+fi
+
+w32pathlist=""
+
+for p in "${patharray[@]}"
+do
+ # Skip empty paths
+ test "$p" = "" && continue
+
+ # Replace '\' with '/' and '//' with '/'
+ p="${p//\\//}"
+ p="${p//\/\///}"
+
+ if test -d "$p"
+ then
+ # The path exists, so just translate it
+ w32p=`cd "$p" && pwd -W`
+ else
+ # The path does not exists. So, try to guess the
+ # Windows-native translation, by looking for the deepest
+ # existing directory in this path, and then translating the
+ # existing part and concatenating the remainder.
+
+ test "${mustexist}" = "Y" &&
+ { echo "${me}: invalid path: $p" >&2; exit 1; }
+
+ p1=$p
+ IFS=/ pcomponents=( $p )
+
+ for (( i=${#pcomponents[@]}-1 ; i>=0 ; i-- ))
+ do
+
+ if test "${pcomponents[i]}" = ""
+ then
+ # The path component is empty. This can only mean
+ # that the path starts with "/" and all components
+ # have been stripped out already. So in this case we
+ # want to test with the MSYS root directory
+ p1="/"
+ else
+ p1="${p1%/}"
+ p1="${p1%${pcomponents[i]}}"
+ fi
+
+ if test -d "${p1}"
+ then
+
+ # Existing path found
+
+ # Translate the existing part and concatenate the
+ # remainder (ensuring that only one slash is used in
+ # the join, and no trailing slash is left)
+ w32p1=`cd "${p1}" && pwd -W`
+ remainder="${p#${p1}}"
+ remainder="${remainder#/}"
+ remainder="${remainder%/}"
+ w32p="${w32p1%/}/${remainder}"
+
+ break
+ fi
+
+ done
+
+ # If no existing directory was found, error out
+ test -e "${p1}" ||
+ { echo "${me}: invalid path: ${p}" >&2; exit 1; }
+ fi
+
+ # Concatenate the translated path to the translated pathlist
+ test "${w32pathlist}" = "" || w32pathlist="${w32pathlist}${separator2}"
+ w32pathlist="${w32pathlist}${w32p//${separator2}/\\${separator2}}"
+
+done
+
+# Write the translated pathlist to the standard output
+printf "${w32pathlist}"