go 1.12 binaries rejected from mac app store due to ___getdirentries64 [1.12 backport]

[gopherbot]

@randall77 requested issue #30933 to be considered for backport to the next 1.12 minor release.

@gopherbot please consider this for backport to 1.12.

[randall77]

This issue prevents binaries built with 1.12 from being uploaded to the macOS App store.
1.11 binaries used to work.

[gopherbot]

Change https://golang.org/cl/170640 mentions this issue: [release-branch.go1.12] syscall: avoid _getdirentries64 on darwin

[gopherbot]

Closed by merging 731ebf4 to release-branch.go1.12.