This patch adds a `make format-cpp` shortcut to the Makefile
that runs clang-format on the C++ diffs, and a
`make format-cpp-build` to install clang-format from
npm.
To format staged changes:
```
$ make format-cpp
```
To format HEAD~1...HEAD (latest commit):
```
$ CLANG_FORMAT_START=`git rev-parse HEAD~1` make format-cpp
```
To format diff between master and current branch head (master...HEAD):
```
$ CLANG_FORMAT_START=master make format-cpp
```
Most of the .clang-format file comes from running
```
$ clang-format --dump-config --style=Google
```
with clang-format built with llvm/trunk 328768 (npm version 1.2.3)
The clang-format version is fixed because different version of
clang-format may format the files differently.
PR-URL: https://github.com/nodejs/node/pull/21997
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
