RFR: 8274548: (fc) FileChannel gathering write fails with IOException "Invalid argument" on macOS 11.6 [v4]

[Brian Burkhalter]

> On macOS, handle the case where `writev()` is given an array of `struct iovec` the sum of whose `iov_len` fields overflows `INT_MAX`.

Brian Burkhalter has updated the pull request incrementally with one additional commit since the last revision:

  8274548: Native macOS-only code change with no modification of iovec array

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/5831/files
  - new: https://git.openjdk.java.net/jdk/pull/5831/files/1d41dfbb..6da2c82e

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=5831&range=03
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=5831&range=02-03

  Stats: 44 lines in 2 files changed: 22 ins; 16 del; 6 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5831.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5831/head:pull/5831

PR: https://git.openjdk.java.net/jdk/pull/5831