homebrewでopensslを入れたら、bundle installでeventmachineのエラーが発生

環境

• MacOSX EL Capitan
• Ruby2.1.7

現象

Macのbundle installで eventmachineのインストールに失敗した

$ bundle install
.
.
.
Installing eventmachine 1.0.5 with native extensions

Gem::Ext::BuildError: ERROR: Failed to build gem native extension.

    /Users/tkmiya34/.anyenv/envs/rbenv/versions/2.1.7/bin/ruby extconf.rb
checking for rb_trap_immediate in ruby.h,rubysig.h... no
checking for rb_thread_blocking_region()... yes
checking for ruby/thread.h... yes
checking for rb_thread_call_without_gvl() in ruby/thread.h... yes
checking for inotify_init() in sys/inotify.h... no
checking for __NR_inotify_init in sys/syscall.h... no
checking for writev() in sys/uio.h... yes
checking for rb_thread_fd_select()... yes
checking for rb_wait_for_single_fd()... yes
checking for rb_enable_interrupt()... no
checking for rb_time_new()... yes
checking for sys/event.h... yes
checking for sys/queue.h... yes
checking for clock_gettime()... no
checking for gethrtime()... no
creating Makefile

make "DESTDIR=" clean

make "DESTDIR="
compiling binder.cpp
In file included from binder.cpp:20:
./project.h:116:10: fatal error: 'openssl/ssl.h' file not found
#include <openssl/ssl.h>
         ^
1 error generated.
make: *** [binder.o] Error 1

make failed, exit code 2

Gem files will remain installed in /Users/tkmiya34/work/startup-technology/yaqs/yaqs-development/vendor/bundle/ruby/2.1.0/gems/eventmachine-1.0.5 for inspection.
Results logged to /Users/tkmiya34/work/startup-technology/yaqs/yaqs-development/vendor/bundle/ruby/2.1.0/extensions/x86_64-darwin-15/2.1.0-static/eventmachine-1.0.5/gem_make.out
An error occurred while installing eventmachine (1.0.5), and Bundler cannot
continue.
Make sure that `gem install eventmachine -v '1.0.5'` succeeds before bundling.

解決方法

エラーメッセージ見たらopensslに問題がありそう。
opensslはhomebrewでインストールしています。

調べてたらeventmachineのGitHub Issueに載っていました

$ brew link openssl --force
Linking /usr/local/Cellar/openssl/1.0.2d_1... 1548 symlinks created

もう一度 bundle installしたらインストール成功しました