According to [1] we need to only call async-signal-safe operations between fork
and exec. Using malloc to build the argv array isn't async-signal-safe.
In order to avoid allocation between 'fork()' and 'exec()' prepare the
argv array used in the exec call prior to forking the process.
[1] http://pubs.opengroup.org/onlinepubs/
009695399/functions/fork.html
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>