This commit adds an asynchronous reading API to let you get the
stdout or stderr of a process while the process is still running.
You cannot use normal C FILE API operations for this - so instead
I've had to add new subprocess_read_stdout and
subprocess_read_stderr helper functions and a
subprocess_option_enable_async option to subprocess_create to enable
this functionality.
This commit adds an asynchronous reading API to let you get the stdout or stderr of a process while the process is still running.
You cannot use normal C FILE API operations for this - so instead I've had to add new
subprocess_read_stdoutandsubprocess_read_stderrhelper functions and asubprocess_option_enable_asyncoption tosubprocess_createto enable this functionality.