[PATCH] configure: fix mktemp call for macOS

[Tomi Ollila]

On Sat, Jun 15 2019, Ralph Seichter wrote:

> * Tomi Ollila:
>
>> First, it would be better if
>>
>> TEMP_GPG=$(mktemp -d "${TMPDIR:-/tmp}/notmuch.XXXXXX")
>>
>> worked, then the behaviour on Linux would not change.
>
> I'm trying to figure out if I can override $TMPDIR during the MacPorts
> configure phase. According to the documentation, modifying environment
> variables should work, but I am not quite there yet.
>
> Corollary: I suggest we go for the method shown above for the time
> being. I am not a fan of hardcoding paths either.

That maintains the status quo, so no-one needs to explain the change
in commit message.

SO I pre-LGTM anyone sending message containing the followin change:

+    if ! TEMP_GPG=$(mktemp -d "${TMPDIR:-/tmp}/notmuch.XXXXXX"); then

Tomi


>
> -Ralph