macOS Sierraでrails5を使おうとしたらmysqlでエラーになった。

こんな感じ

省略...

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

    current directory: /usr/local/var/rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/mysql2-0.4.5/ext/mysql2
/usr/local/var/rbenv/versions/2.3.1/bin/ruby -r ./siteconf20170321-38342-1u8g6eb.rb extconf.rb

省略...

-----
Don't know how to set rpath on your system, if MySQL libraries are not in path mysql2 may not load
-----
-----
Setting libpath to /usr/local/Cellar/mysql/5.7.17/lib
-----
creating Makefile

current directory: /usr/local/var/rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/mysql2-0.4.5/ext/mysql2
make "DESTDIR=" clean

current directory: /usr/local/var/rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/mysql2-0.4.5/ext/mysql2
make "DESTDIR="
compiling client.c
compiling infile.c
compiling mysql2_ext.c
compiling result.c
compiling statement.c
linking shared-object mysql2/mysql2.bundle
ld: library not found for -lssl
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [mysql2.bundle] Error 1

make failed, exit code 2

Gem files will remain installed in /usr/local/var/rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/mysql2-0.4.5 for inspection.
Results logged to
/usr/local/var/rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/extensions/x86_64-darwin-16/2.3.0-static/mysql2-0.4.5/gem_make.out

An error occurred while installing mysql2 (0.4.5), and Bundler cannot continue.
Make sure that `gem install mysql2 -v '0.4.5'` succeeds before bundling.
         run  bundle exec spring binstub --all
Could not find gem 'mysql2 (< 0.5, >= 0.3.18)' in any of the gem sources listed in your Gemfile or available on this machine.
Run `bundle install` to install missing gems.

なんだかよくわからんがmysql2のビルドに失敗している、と。

とりあえず、

$ gem install mysql2 -v '0.4.5'

を実行。

Building native extensions.  This could take a while...
ERROR:  Error installing mysql2:
    ERROR: Failed to build gem native extension.

    current directory: /usr/local/var/rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/mysql2-0.4.5/ext/mysql2
/usr/local/var/rbenv/versions/2.3.1/bin/ruby -r ./siteconf20170321-55696-zu02ml.rb extconf.rb
checking for rb_absint_size()... yes
checking for rb_absint_singlebit_p()... yes
checking for ruby/thread.h... yes
checking for rb_thread_call_without_gvl() in ruby/thread.h... yes
checking for rb_thread_blocking_region()... no
checking for rb_wait_for_single_fd()... yes
checking for rb_hash_dup()... yes
checking for rb_intern3()... yes
checking for rb_big_cmp()... yes
-----
Using mysql_config at /usr/local/bin/mysql_config
-----
checking for mysql.h... yes
checking for SSL_MODE_DISABLED in mysql.h... yes
checking for SSL_MODE_PREFERRED in mysql.h... yes
checking for SSL_MODE_REQUIRED in mysql.h... yes
checking for SSL_MODE_VERIFY_CA in mysql.h... yes
checking for SSL_MODE_VERIFY_IDENTITY in mysql.h... yes
checking for errmsg.h... yes
checking for mysqld_error.h... yes
-----
Don't know how to set rpath on your system, if MySQL libraries are not in path mysql2 may not load
-----
-----
Setting libpath to /usr/local/Cellar/mysql/5.7.17/lib
-----
creating Makefile

current directory: /usr/local/var/rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/mysql2-0.4.5/ext/mysql2
make "DESTDIR=" clean

current directory: /usr/local/var/rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/mysql2-0.4.5/ext/mysql2
make "DESTDIR="
compiling client.c
compiling infile.c
compiling mysql2_ext.c
compiling result.c
compiling statement.c
linking shared-object mysql2/mysql2.bundle
ld: library not found for -lssl
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [mysql2.bundle] Error 1

make failed, exit code 2

Gem files will remain installed in /usr/local/var/rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/mysql2-0.4.5 for inspection.
Results logged to /usr/local/var/rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/extensions/x86_64-darwin-16/2.3.0-static/mysql2-0.4.5/gem_make.out

はい。やっぱダメでしたね。

エラーの内容を見たら

checking for rb_thread_blocking_region()... no

とのこと。 色々ググったら

nekonenene.hatenablog.com

こちらの解決策1と解決策3 を実行したらうまくいきました。

ははぁ、、、

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