Changed proc_open() zpp argument to separate the environment array

[datibbaw]

This fixes https://bugs.php.net/bug.php?id=60602

The convert_to_string_ex() was modifying the underlying array while creating the environment string, so I've tweaked the respective zpp argument.

[nikic]

Why does ! fix this bug? Do you maybe mean /? But in any case, I'd prefer to change the string cast (copy to local zval + convert_to_string) rather than doing a full zval separation on the array here.