Guile CVS uses mmap without checking for it in configure

[Steven G. Johnson]

Hi, I am trying to compile the Guile CVS version on a Cray T3E (under
UNICOS), and encountered a problem because the CVS version uses mmap (in
dump.c), which is not available on that system.

Ideally, the configure script should check to see if mmap is available and
disable the related functionality (or use a workaround?) if it is not.  The
configure test is trivial, of course, but I'm not sure how dump.c fits into
the grand scheme of things, so I'll leave it to someone else to suggest the
appropriate patch.

For now, I've just commented out dump.c and am looking at what is required
for gc_os_dep.c (the next thing that breaks the compilation...sigh).

Steven