##### http://autoconf-archive.cryp.to/ac_prog_cp_s.html
#
# SYNOPSIS
#
#   AC_PROG_CP_S
#
# DESCRIPTION
#
#   Check how to make a copy by creating a symbolic link to the
#   original - it defines the variable CP_S for further use, which you
#   should in fact treat like it used to be with be LN_S. The actual
#   value is assured to be either LN_S (if the filesystem supports
#   symbolic links) or CP (if the filesystem does not know about
#   symbolic links and you need a copy of original file to have the
#   same text in both places). In a gnu environment it will simply set
#   CP_S="cp -s" since the gnu "cp"-command has the "-s" flag. You
#   shall not try to use this command on directories since it would
#   require a "-r" in the case of a copy that is not supported
#   explicitly here. (I'm not sure if some "cp"-commands out there
#   would barf at usage of "-r" on a normal file).
#
#   Use CP_S to create a copy of read-only data - if your filesystem
#   supports it then a symbolic link is created - a process that is
#   quicker and space-saving. However, if the target fs does not
#   support symbolic links, just copy the data. Unlike ac_prog_ln_s
#   this macro will never fail to set the CP_S ac_subst to something
#   that works.
#
# LAST MODIFICATION
#
#   2006-10-13
#
# COPYLEFT
#
#   Copyright (c) 2006 Guido U. Draheim <guidod@gmx.de>
#
#   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 2 of the
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#
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#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
#   General Public License for more details.
#
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#   02111-1307, USA.
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AC_DEFUN([AC_PROG_CP_S],
[AC_REQUIRE([AC_PROG_LN_S])dnl
AC_MSG_CHECKING(whether cp -s works)
AC_CACHE_VAL(ac_cv_prog_CP_S,
[rm -f conftestdata
if cp -s X conftestdata 2>/dev/null
then
  rm -f conftestdata
  ac_cv_prog_CP_S="cp -s"
else
  ac_cv_prog_CP_S=cp
fi
if test "$LN_S" = "ln -s" ; then
  ac_cv_prog_CP_S="ln -s"
fi])dnl
CP_S="$ac_cv_prog_CP_S"
if test "$ac_cv_prog_CP_S" = "ln -s"; then
  AC_MSG_RESULT(using ln -s)
elif test "$ac_cv_prog_CP_S" = "cp -s"; then
  AC_MSG_RESULT(yes)
else
  AC_MSG_RESULT(no, using cp)
fi
AC_SUBST(CP_S)dnl
])