On Windows, limit which file handles are inherited by spawned child processes

This is yet another of those patch series that matured in Git for Windows for over a year before being "upstreamed".

The problem to be solved: files cannot be deleted on Windows when even one process has an open file handle to it. So when a process opens a temporary file, then spawns a child process that inherits that file handle by mistake, and then the parent process tries to delete the temporary file while the child process is still running, the deletion will fail. (This description is slightly simplified, see the commit message "spawned processes need to inherit only standard handles" for more detail.)

Technically, we might want to squash "restrict file handle inheritance only on Windows 7 and later" into "spawned processes need to inherit only standard handles", but while preparing this patch series, I found the story easier to follow with them still being separate.

The real reason why I submit this now is that I needed some ready-to-submit patch series as an excuse to test GitGitGadget on https://github.com/git/git
.

Johannes Schindelin (4):
mingw: demonstrate that all file handles are inherited by child
processes
mingw: work around incorrect standard handles
mingw: spawned processes need to inherit only standard handles
mingw: restrict file handle inheritance only on Windows 7 and later

 Documentation/config/core.txt |   6 ++
 compat/mingw.c                | 140 +++++++++++++++++++++++++++++++---
 compat/winansi.c              |  12 ++-
 t/helper/test-run-command.c   |  44 +++++++++++
 t/t0061-run-command.sh        |   4 +
 5 files changed, 194 insertions(+), 12 deletions(-)

base-commit: d9f6f3b6195a0ca35642561e530798ad1469bd41
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-670%2Fdscho%2Finherit-only-stdhandles-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-670/dscho/inherit-only-stdhandles-v1
Pull-Request: https://github.com/git/git/pull/670

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