我收到了这个错误:
sudo gem install mysql2
Building native extensions. This could take a while...
ERROR: Error installing mysql2:
ERROR: Failed to build gem native extension.
/usr/bin/ruby1.8 extconf.rb
checking for rb_thread_blocking_region()... no
checking for mysql.h... no
checking for mysql/mysql.h... no
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mysql.h is missing. please check your installation of mysql and try again.
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*** 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 …