macOS High Sierra で Ansible 入れようとしたら失敗した。

Homebrew で Ansible 入れようとしたら失敗しました。
環境：macOS High Sierra 10.13

```sh
$ brew install ansible
```
```sh
==> Installing ansible dependency: gdbm
==> Downloading https://homebrew.bintray.com/bottles/gdbm-1.13.high_sierra.bottle.tar.gz
######################################################################## 100.0%
==> Pouring gdbm-1.13.high_sierra.bottle.tar.gz
Error: The `brew link` step did not complete successfully
The formula built, but is not symlinked into /usr/local
Could not symlink include/gdbm.h
/usr/local/include is not writable.
```
```sh
==> Installing ansible dependency: libyaml
==> Downloading https://homebrew.bintray.com/bottles/libyaml-0.1.7.high_sierra.bottle.tar.gz
######################################################################## 100.0%
==> Pouring libyaml-0.1.7.high_sierra.bottle.tar.gz
Error: The `brew link` step did not complete successfully
The formula built, but is not symlinked into /usr/local
Could not symlink include/yaml.h
/usr/local/include is not writable.
```
```sh
==> Installing ansible dependency: python
Warning: Building python from source:
  The bottle needs the Apple Command Line Tools to be installed.
  You can install them, if desired, with:
    xcode-select --install

==> Downloading https://www.python.org/ftp/python/2.7.14/Python-2.7.14.tar.xz
######################################################################## 100.0%
==> ./configure --prefix=/usr/local/Cellar/python/2.7.14 --enable-ipv6 --datarootdir=/usr/local/Cellar/python/2.7.14/share --datadir=/usr/local/Cellar/p
==> make
==> make install PYTHONAPPSDIR=/usr/local/Cellar/python/2.7.14
==> make frameworkinstallextras PYTHONAPPSDIR=/usr/local/Cellar/python/2.7.14/share/python
==> Downloading https://files.pythonhosted.org/packages/a4/c8/9a7a47f683d54d83f648d37c3e180317f80dc126a304c45dc6663246233a/setuptools-36.5.0.zip
######################################################################## 100.0%
==> Downloading https://files.pythonhosted.org/packages/11/b6/abcb525026a4be042b486df43905d6893fb04f05aac21c32c638e939e447/pip-9.0.1.tar.gz
######################################################################## 100.0%
==> Downloading https://files.pythonhosted.org/packages/fa/b4/f9886517624a4dcb81a1d766f68034344b7565db69f13d52697222daeb72/wheel-0.30.0.tar.gz
######################################################################## 100.0%
Error: An unexpected error occurred during the `brew link` step
The formula built, but is not symlinked into /usr/local
Permission denied @ dir_s_mkdir - /usr/local/lib
Error: Permission denied @ dir_s_mkdir - /usr/local/lib
```

/usr/local/lib とか /usr/local/include に書き込み権限がないみたいです。
解決策調べてたら、単純に sudo chown -R $(whoami) $(brew --prefix) で権限変更しろというのがあったのでやってみましたが失敗。

```sh
$ sudo chown -R $(whoami) $(brew --prefix)
chown: /usr/local: Operation not permitted
```

どうも High Sierra からは上記の操作ができなくなったようです。
https://github.com/Homebrew/brew/issues/3228

結論は上記リンクに書いてありますが、/usr/local/以下のディレクトリを個別に chown で対処できました。必要なディレクトリは先に mkdir しておく必要があります。

```sh
$ sudo mkdir /usr/local/lib
$ sudo mkdir /usr/local/include
$ sudo mkdir /usr/local/Frameworks
$ sudo mkdir /usr/local/Frameworks/Python.framework
$ sudo chown -R $(whoami) $(brew --prefix)/*
```
上記を実行後、Ansible インストールで失敗したところをやりなおして終了。

```sh
$ brew link gdbm
Linking /usr/local/Cellar/gdbm/1.13... 12 symlinks created
$ brew link libyaml
Linking /usr/local/Cellar/libyaml/0.1.7... 5 symlinks created
$ brew link python
Linking /usr/local/Cellar/python/2.7.14... 26 symlinks created
```