refactored call_external code

unluckily here the code neglected the fact that glib will set an error
to a location that was pointed by the error pointer if it is not null.
but it was of an undefined value hence profanity crashed. now it is null
as it must be.

also spawn error is returned when glib could not spawn the task for
some reason like the executable file does not exist but if the exit
status was non-zero it neglected the exit error and tried to output a
spawn error instead. now we check whether the process that we
instantiated has exited successfully

also now code uses `g_spawn_check_wait_status` which
`g_spawn_check_exit_status` has been aliased to.

0 files changed, 0 insertions, 0 deletions