Fixes a regression on OS X introduced by f83af95.
Don't use --tmpdir for mktemp, because that flag doesn't exist on OS X.
However, using -t is deprecated in GNU coreutils, so as suggested by
@ip1981 we're now using parameter expansion on ${TMPDIR:-/tmp} to
provide /tmp as a fallback if TMPDIR is not set and use it instead.
Also use this approach for nix-prefetch-cvs now in order to stay
consistent.
Reported-by: Vladimir Kirillov <proger@wilab.org.ua>
Tested-by: Igor Pashev <pashev.igor@gmail.com>
Signed-off-by: aszlig <aszlig@redmoonstudios.org>
Instead of relying on $$ to not collide with an existing path.
Quoting the Bash manual about $$:
> Expands to the process ID of the shell. In a () subshell, it expands
> to the process ID of the current shell, not the subshell.
So, this is different from $BASHPID:
> Expands to the process ID of the current bash process. This differs
> from $$ under certain circumstances, such as subshells that do not
> require bash to be re-initialized.
But even $BASHPID is prone to race conditions if the process IDs wrap
around, so to be on the safe side, we're using mktemp here.
Closes#3784.
Signed-off-by: aszlig <aszlig@redmoonstudios.org>
