Mac OS Mojave 10.14.5
我在Rails的ruby中安装mysql gem时遇到问题。我运行捆绑安装后，将显示以下消息：
Fetching mysql2 0.4.4
Installing mysql2 0.4.4 with native extensions
Gem::Ext::BuildError: ERROR: Failed to build gem native extension.
current directory:
/Users/urijkunicyn/.rvm/gems/ruby-2.3.1/gems/mysql2-0.4.4/ext/mysql2
/Users/urijkunicyn/.rvm/rubies/ruby-2.3.1/bin/ruby -I
/Users/urijkunicyn/.rvm/rubies/ruby-2.3.1/lib/ruby/site_ruby/2.3.0 -r
./siteconf20190606-13348-77enf9.rb extconf.rb
checking for ruby/thread.h... *** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers. Check the mkmf.log file for more details. You may need configuration options.
Provided configuration options:
--with-opt-dir
--with-opt-include
--without-opt-include=${opt-dir}/include
--with-opt-lib
--without-opt-lib=${opt-dir}/lib
--with-make-prog
--without-make-prog
--srcdir=.
--curdir
--ruby=/Users/urijkunicyn/.rvm/rubies/ruby- 2.3.1/bin/$(RUBY_BASE_NAME)
/Users/urijkunicyn/.rvm/rubies/ruby- 2.3.1/lib/ruby/2.3.0/mkmf.rb:456:in
`try_do': The compiler failed to generate an executable file. (RuntimeError)
You have to install development tools first.
from /Users/urijkunicyn/.rvm/rubies/ruby- 2.3.1/lib/ruby/2.3.0/mkmf.rb:587:in
try_cpp'
from /Users/urijkunicyn/.rvm/rubies/ruby- 2.3.1/lib/ruby/2.3.0/mkmf.rb:1091:in
在have_header中被屏蔽'
来自/Users/urijkunicyn/.rvm/rubies/ruby- 2.3.1 / lib / ruby / 2.3.0 / mkmf.rb：942：in
block in checking_for'
from /Users/urijkunicyn/.rvm/rubies/ruby- 2.3.1/lib/ruby/2.3.0/mkmf.rb:350:in
阻止（2个级别）推迟”
来自/Users/urijkunicyn/.rvm/rubies/ruby- 2.3.1 / lib / ruby / 2.3.0 / mkmf.rb：320：in
open'
from /Users/urijkunicyn/.rvm/rubies/ruby- 2.3.1/lib/ruby/2.3.0/mkmf.rb:350:in
阻止推迟”
来自/Users/urijkunicyn/.rvm/rubies/ruby- 2.3.1 / lib / ruby / 2.3.0 / mkmf.rb：320：in
open'
from /Users/urijkunicyn/.rvm/rubies/ruby-2.3.1/lib/ruby/2.3.0/mkmf.rb:346:in
推迟”
来自/Users/urijkunicyn/.rvm/rubies/ruby-2.3.1/lib/ruby/2.3.0/mkmf.rb:941:in
checking_for'
from /Users/urijkunicyn/.rvm/rubies/ruby-2.3.1/lib/ruby/2.3.0/mkmf.rb:1090:in
have_header'
来自extconf.rb：16：in''
要查看此扩展为何无法编译，请检查mkmf.log，该文件可以 在这里找到：
/Users/urijkunicyn/.rvm/gems/ruby-2.3.1/extensions/x86_64-darwin-16/2.3.0/mysql2-0.4.4/mkmf.log
extconf失败，退出代码1
宝石文件将继续安装在 /Users/urijkunicyn/.rvm/gems/ruby-2.3.1/gems/mysql2-0.4.4进行检查。 结果记录到 /Users/urijkunicyn/.rvm/gems/ruby-2.3.1/extensions/x86_64-darwin-16/2.3.0/mysql2-0.4.4/gem_make.out
在安装mysql2（0.4.4）时发生错误，并且Bundler无法
继续。
确保gem install mysql2 -v '0.4.4' --source 'https://rubygems.org/'
捆绑前成功。