In sysctl_proc_cwd(), vref() the target proc's fd_cdir before calling malloc(), so that it can't exit and be freed if we sleep.
In sysctl_proc_cwd(), vref() the target proc's fd_cdir before calling
malloc(), so that it can't exit and be freed if we sleep.

(another sparc.p nightmare test case)
ok beck@, phessler@

orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars