Using hidden files are rather antisocial, and rather pointless in this
particular context. Change .stdout and .stderr to simply stdout and
stderr.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Correct the implementation of %arg and %local.
It's questionable how much they make sense for 64-bit mode; even in
32-bit mode one normally make references off the stack pointer instead
of the base pointer (frame pointer), but that requires keeping track
of the stack pointer offset.