INSTALL_AS_USER and INSTALL_AS_GROUP

[Nicola Pero]

I've just finished implementing INSTALL_AS_USER and INSTALL_AS_GROUP in
gnustep-make.

Most people don't need this ever - but in some cases it's really useful.

It means that now you can define in your GNUmakefile (at the beginning or
in the GNUmakefile.preamble) the variables INSTALL_AS_USER and/or
INSTALL_AS_GROUP, as in the following example -

INSTALL_AS_USER  = nicola
INSTALL_AS_GROUP = users

and anything which is installed will get chowned to nicola.users.

If you don't specify them, all works as before - everything is installed
normally with the user and group of the user who is installing.

Setting INSTALL_AS_USER and/or INSTALL_AS_ROOT causes:

 * INSTALL, INSTALL_DATA and INSTALL_PROGRAM to specify the owner and/or
   group to use when installing the file;

 * application.make, bundle.make, and the other makefiles installing
   software using tar to recursively chown the installed directory
   to the owner and/or group;

 * MKINSTALLDIRS to chown the created installation directories to the
   appropriate owner and/or group. (MKINSTALLDIRS is a new variable, 
   the usual one, which is MKDIRS, still creates directories ignoring
   INSTALL_AS_USER and INSTALL_AS_GROUP.  The idea is that you use
   MKDIRS to create local directories, and MKINSTALLDIRS to create 
   installation directories - difference being the MKINSTALLDIRS 
   potentially chowns the created dirs).

This means that if you add installation rules in your
GNUmakefile.postamble, those rules will automatically use the appropriate
INSTALL_AS_USER and INSTALL_AS_GROUP if you follow the following simple
guidelines:

 * you always install using INSTALL, INSTALL_DATA and INSTALL_PROGRAM; 
   don't use cp to install (if you do, you have to chown the result
   manually);

 * you always create installation directories using MKINSTALLDIRS and not 
   MKDIRS. (but create local dirs using MKDIRS - *not* MKINSTALLDIRS);

 * if you install anything manually outside these rules, you need to chown
   the installed file/dir/whatever as in the following example - 

ifneq ($(CHOWN_TO),)
        chown $(CHOWN_TO) $(MY_INSTALLED_FILE)
endif

   if it is a directory, use something like 'chown -R $(CHOWN_TO) 
   $(MY_INSTALLED_DIR)'