unix: OpenURL: Move unsetenv above vfork From the vfork manpage: > The vfork() function has the same effect as fork(2), except that > the behavior is undefined if the process created by vfork() either > modifies any data other than a variable of type pid_t used to store > the return value from vfork(), or returns from the function in which > vfork() was called, or calls any other function before successfully > calling _exit(2) or one of the exec(3) family of functions. unsetenv is still called inside a child process, so it does not influence the rest of the application.