安装完成 ffmpeg 出现动态库 libicui18n 报错，不存在
$ php -v
dyld: Library not loaded: /usr/local/opt/icu4c/lib/libicui18n.63.dylib
Referenced from: /usr/local/opt/php@7.2/bin/php
Reason: image not found
[1] 31174 abort php -v 通过网上查找资料了解到 php 新版本的动态库 7.2.16 不能使用 63 版本，通过升级 php 可以解决问题。
使用 brew 升级 php
$ brew upgrade php72
==> Upgrading 1 outdated package:
php@7.2 7.2.16 -> 7.2.20
==> Upgrading php@7.2
==> Installing dependencies for php@7.2: apr, argon2, libssh2, jemalloc, libev, nghttp2, curl-openssl, freetds, libpq and libsodium
==> Installing php@7.2 dependency: apr
==> Downloading https://homebrew.bintray.com/bottles/apr-1.7.0.mojave.bottle.tar.gz
==> Downloading from https://akamai.bintray.com/3a/3a245185ed7280d1a19e7c639786b4c21dd0088878be8ac87ca58510eb5c9cc1?__gda__=exp=1563530722~hmac=8e94698ea6aa458b7dfea49d1cde602217ab9a2
######################################################################## 100.0%
==> Pouring apr-1.7.0.mojave.bottle.tar.gz
==> Caveats
apr is keg-only, which means it was not symlinked into /usr/local,
because Apple's CLT package contains apr.
If you need to have apr first in your PATH run:
echo 'export PATH="/usr/local/opt/apr/bin:$PATH"' >> ~/.zshrc一切结束之后执行 php 查看版本：
$ php -v
PHP 7.2.20 (cli) (built: Jul 5 2019 12:51:26) (NTS)
Copyright (c) 1997-2018 The PHP Group
Zend Engine v3.2.0, Copyright (c) 1998-2018 Zend Technologies
with Zend OPcache v7.2.20, Copyright (c) 1999-2018, by Zend Technologies