Signed-off-by: Wolfgang Denk <wd@denx.de>
[trini: Fixup common/cmd_io.c]
Signed-off-by: Tom Rini <trini@ti.com>

At least on OS X 10.5 and older, getline does not exist.  So split out the
function from the mingw code so that we can pull it in for Darwin systems.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>