Fix Makefile.in in data-directory

[Joel Brobecker]

> ># Traditionally "install" depends on "all".  But it may be useful
> ># not to; for example, if the user has made some trivial change to a
> ># source file and doesn't care about rebuilding or just wants to save the
> ># time it takes for make to check that all is up to date.
> ># install-only is intended to address that need.
> >install: all install-only 
> 
> (enphasis on the comment.)  Maybe it's the 'Traditionally "install" depends
> on "all".' part that's not so traditional afterall?  I really don't know.
> 
> (most users are better taught separate "make" and "make install" steps,
> because it's most often necessary to need extra previleges
> and "sudo make install" to install to /usr/local, but not to "make".)

AFAIK, the FSF recommends against making "make install" also do the build.

-- 
Joel