Users should set the `sys_temp_dir` directive.
PHAR stores temporary files in either `sys_temp_dir` or the current working directory(CWD).
This is especially important if you're CWD is on a remote file system. Often web server clusters will share a common file system between each web server (using NFS, DFS, etc...). In such scenarios, if you don't set `sys_temp_dir` to a local directory, PHAR will be creating temporary files over the network, which will result in performance and functionality problems.
