V3 Configury

[David Edelsohn]

	Maybe a better approach is a combination of:

1) More efficient autoconf machinery to not save and restore the cache
after each test.

2) Continued use of individual tests, but...

3) Use config.target to avoid tests on platforms known to not need the
detailed inquiry.

	A similar area is the ctype tests where it takes significant time
to realize that AIX does not support GNU/Linux, *BSD, Solaris*, Irix, or
newlib ctype design.  We already know the target system, so we might as
well only test for the existence of that system's ctype.

	That's my recommendation for decreasing the configure time without
missing subtle changes in new OS releases.

David