busybox

scripts: fix fixdep.c to let it workable in cygwin

Update retrun character detection in the fixdep.c
to let it work in cygwin.

Signed-off-by: Macpaul Lin <macpaul@andestech.com>
Signed-off-by: Greentime <green.hu@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>