bug#14576: "make install" has trouble with non-standard locallisppath directories

[Juanma Barranquero <lekktu@gmail.com>]

Package: emacs
Version: 24.3.50

On Windows, using the MSYS build machinery.

If you need to add a non-default lisp directory to the path, by
following nt/INSTALL.MSYS recommendation of doing, for example

  ./nt/msysconfig.sh
--enable-locallisppath='%emacs_dir%/../site-lisp;%emacs_dir%/share/emacs/24.3.50/site-lisp;%emacs_dir%/share/emacs/site-lisp'

then "make install" will try to create these directories *in the build
tree* (not the installation dir), and do a poor job at it. In the
above case, after make install the build tree will contain these
directories:

 %emacs_dir%
 site-lisp;%emacs_dir%/share/emacs/24.3.50/site-lisp;%emacs_dir%/share/emacs/site-lisp

"%emacs_dir%" is literal, an unexpanded environment variable.

Makefile.in contains this old note:

  ## I'm not sure creating locallisppath here serves any useful purpose.
  ## If it has the default value, then the later write_subdir commands
  ## will ensure all these components exist.
  ## This will only do something if locallisppath has a non-standard value.
  ## Is it really Emacs's job to create those directories?
  ## Should we also be ensuring they contain subdirs.el files?
  ## It would be easy to do, just use write_subdir.

and indeed, I would argue that is not Emacs' job to create them. If
the user is knowledgeable enough to have to use
--enable-locallisppath, s/he'll also know enough to make sure the
directories exist and contain subdirs.el as required.