git: openjdk/jdk: 8274293: Build failure on macOS with Xcode 13.0 as vfork is deprecated

[Jie Fu]

Changeset: 252aaa92
Author:    bobpengxie <bobpengxie at tencent.com>
Committer: Jie Fu <jiefu at openjdk.org>
Date:      2021-09-26 14:48:19 +0000
URL:       https://git.openjdk.java.net/jdk/commit/252aaa9249d8979366b37d59487b5b039d923e35

8274293: Build failure on macOS with Xcode 13.0 as vfork is deprecated

Reviewed-by: alanb, stuefe, rriggs

! src/hotspot/os/posix/os_posix.cpp
! src/java.base/unix/native/libjava/ProcessImpl_md.c