Replace outdated help message with a reference to README.  Update README
for make *config variants and environment variable info.
Signed-off-by: NRandy Dunlap <rdunlap@xenotime.net>
Acked-by: NSam Ravnborg <sam@ravnborg.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>