Merge branch 'js/unmap-before-ext-diff' into maint

Windows update. * js/unmap-before-ext-diff: diff: munmap() file contents before running external diff

Junio C Hamano committed Jul 29, 2019 at 12:38 UTC 58f6cfd8ce3c4621d4a772b81b7c92f7519154f1

No changes.