AC_PROG_LN_S limitation

[Werner LEMBERG]

I've received the following bug report from Eli:

  I've built Groff 1.21 on MS-Windows using the MinGW tools, and hit a
  small snag when installing the result.  The `install' target in the
  top-level Makefile ends with this command

          $(LN_S) $(version)$(revision) current

  Since native Windows does not support symlinks, LN_S is set to by
  the `configure' script "cp -p".  However, "cp -p" by default skips
  directories, so this last command fails and the `current' directory
  is not produced.

  I fixed that by saying "make install LN_S='cp -pr'", but I suggest
  to modify the configury to DTRT out of the box in this case.

I wasn't aware of this limitation, and usually I look up autoconf.texi
for such details.  However, this isn't described.

Can this be documented, please?  Or what about making AC_PROG_LN_S
work for directories also by falling back to `cp -pr'?


   Werner