abuild: preserve attributes without setfattr/getfattr

The setfattr/getfattr commands were not guaranteed to be available and
abuild wouldn't properly error when they are not. That may cause some
hidden issues.

Changing the code to not need setfattr/getfattr like it is done in
default_dbg ([3ad93d9a]) and pacman mkpkg ([pacman@88d054093c1]).

The code works by first writing the stripped output into a temporary file
and then replace the contents of the already existing file without changing
any file metadata.

[3ad93d9a]: alpine/abuild@3ad93d9a
[pacman@88d054093c1]: https://gitlab.archlinux.org/pacman/pacman/-/commit/88d054093c1c99a697d95b26bd9aad5bc4d8e170