[plt-scheme] why --enable-macprefix?

At Wed, 9 Sep 2009 12:49:32 -0700 (PDT), Peter Michaux wrote:
> What is the purpose of not allowing by default the --prefix option
> when running ./configure? I see that --enable-macprefix will allow --
> prefix to be used. Is there some problem that will arise on a Mac if --
> prefix is used?

I've added the following note to the Mac OS X section of src/README:

 * To use --prefix without --enable-xonx, you must also supply
   --enable-macprefix. BEWARE! The directory structure for a non-xonx
   build does not fit a typical Unix directory structure. For example,
   frameworks are written directly to a "lib" subdirectory, and
   executables like "MrEd.app" are written directory to the prefix
   directory. (Requiring --enable-macprefix with --prefix for a
   non-xonx build helps prevent accidental installation of a Mac-style
   directory structure on top of an existing Unix-style directory
   structure.)