gem install mysql [--should-be-easy [--on-a-mac-anyway]]

So after upgrading to Ruby 1.9.2 and Rails 3 all at once on my shiny new Snow Leopard macbook, (a foolish thing to do! One step at a time! Isolate errors!), after patching my rails app all over the place till rails_upgrade stops whining, and after a gentle reminder to sudo gem install mysql, I get this:

=> Booting WEBrick
=> Rails 3.0.0 application starting in development on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
[2010-10-18 23:29:34] INFO  WEBrick 1.3.1
[2010-10-18 23:29:34] INFO  ruby 1.9.2 (2010-08-18) [x86_64-darwin10]
[2010-10-18 23:29:34] INFO  WEBrick::HTTPServer#start: pid=8426 port=3000
dyld: lazy symbol binding failed: Symbol not found: _mysql_init
  Referenced from: /opt/local/lib/ruby1.9/gems/1.9.1/gems/mysql-2.8.1/lib/mysql_api.bundle
  Expected in: flat namespace

dyld: Symbol not found: _mysql_init
  Referenced from: /opt/local/lib/ruby1.9/gems/1.9.1/gems/mysql-2.8.1/lib/mysql_api.bundle
  Expected in: flat namespace

Trace/BPT trap

A search for "lazy symbol binding failed: Symbol not found: _mysql_init" yields this, this, and this ... pointing out that you don't get the wonderful mysql gem without a *little* bit of effort ... but:

$ sudo env ARCHFLAGS="-arch i386" gem install mysql -- --with-mysql-dir=/usr/local/mysql --with-mysql-lib=/usr/local/mysql/lib --with-mysql-include=/usr/local/mysql/include --with-mysql-config=/usr/local/mysql/bin/mysql_config
Building native extensions.  This could take a while...
ERROR:  Error installing mysql:
 ERROR: Failed to build gem native extension.

/opt/local/bin/ruby extconf.rb --with-mysql-dir=/usr/local/mysql --with-mysql-lib=/usr/local/mysql/lib --with-mysql-include=/usr/local/mysql/include --with-mysql-config=/usr/local/mysql/bin/mysql_config
checking for mysql_ssl_set()... *** 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=/opt/local/bin/ruby
 --with-mysql-config
/opt/local/lib/ruby1.9/1.9.1/mkmf.rb:368:in `try_do': The complier failed to generate an executable file. (RuntimeError)
You have to install development tools first.
 from /opt/local/lib/ruby1.9/1.9.1/mkmf.rb:435:in `try_link0'
 from /opt/local/lib/ruby1.9/1.9.1/mkmf.rb:440:in `try_link'
 from /opt/local/lib/ruby1.9/1.9.1/mkmf.rb:552:in `try_func'
 from /opt/local/lib/ruby1.9/1.9.1/mkmf.rb:797:in `block in have_func'
 from /opt/local/lib/ruby1.9/1.9.1/mkmf.rb:693:in `block in checking_for'
 from /opt/local/lib/ruby1.9/1.9.1/mkmf.rb:280:in `block (2 levels) in postpone'
 from /opt/local/lib/ruby1.9/1.9.1/mkmf.rb:254:in `open'
 from /opt/local/lib/ruby1.9/1.9.1/mkmf.rb:280:in `block in postpone'
 from /opt/local/lib/ruby1.9/1.9.1/mkmf.rb:254:in `open'
 from /opt/local/lib/ruby1.9/1.9.1/mkmf.rb:276:in `postpone'
 from /opt/local/lib/ruby1.9/1.9.1/mkmf.rb:692:in `checking_for'
 from /opt/local/lib/ruby1.9/1.9.1/mkmf.rb:796:in `have_func'
 from extconf.rb:50:in `
'


Gem files will remain installed in /opt/local/lib/ruby1.9/gems/1.9.1/gems/mysql-2.8.1 for inspection.
Results logged to /opt/local/lib/ruby1.9/gems/1.9.1/gems/mysql-2.8.1/ext/mysql_api/gem_make.out

"You have to install development tools first." ... thanks dudes ... but sudo port instal mysql-devel tells me Error: Port mysql_devel not found. What are these mysterious development tools?

Someone recommends copying the output of mysql_config --cflags to the ARCHFLAGS env var, but still no go:

$ mysql_config
Usage: /usr/local/mysql/bin/mysql_config [OPTIONS]
Options:
        --cflags         [-I/usr/local/mysql/include -Os -arch i386 -fno-common]
        --include        [-I/usr/local/mysql/include]
        --libs           [-L/usr/local/mysql/lib -lmysqlclient -lz -lm]
        --libs_r         [-L/usr/local/mysql/lib -lmysqlclient_r -lz -lm]
        --socket         [/tmp/mysql.sock]
        --port           [3306]
        --version        [5.0.37]
        --libmysqld-libs [-L/usr/local/mysql/lib -lmysqld -lz -lm]

$ sudo env ARCHFLAGS="-Os -arch i386 -fno-common" gem install mysql -- --with-mysql-dir=/usr/local/mysql --with-mysql-lib=/usr/local/mysql/lib --with-mysql-include=/usr/local/mysql/include --with-mysql-config=/usr/local/mysql/bin/mysql_config
all the same errors, all over again

The usual drill, I run these commands a few times to make sure they don't change their minds if I insist politely ... no bacon. But what's the deal with mysql_config5? ... it turns out that it's *not* the same as mysql_config ... it's not the same thing at all, and it has completely different output:

$ mysql_config5
Usage: /opt/local/bin/mysql_config5 [OPTIONS]
Options:
        --cflags         [-I/opt/local/include/mysql5/mysql  -pipe -fPIC    -D_P1003_1B_VISIBLE -DSIGNAL_WITH_VIO_CLOSE -DSIGNALS_DONT_BREAK_READ -DIGNORE_SIGHUP_SIGQUIT  -DDONT_DECLARE_CXA_PURE_VIRTUAL]
        --include        [-I/opt/local/include/mysql5/mysql]
        --libs           [-L/opt/local/lib   -L/opt/local/lib/mysql5/mysql -lmysqlclient -L/opt/local/lib -lz -lm  -L/opt/local/lib/ -lssl -lcrypto]
        --libs_r         [-L/opt/local/lib   -L/opt/local/lib/mysql5/mysql -lmysqlclient_r -L/opt/local/lib -lz -lm   -L/opt/local/lib/ -lssl -lcrypto]
        --plugindir      [/opt/local/lib/mysql5/mysql/plugin]
        --socket         [/opt/local/var/run/mysql5/mysqld.sock]
        --port           [0]
        --version        [5.1.51]
        --libmysqld-libs [-L/opt/local/lib   -L/opt/local/lib/mysql5/mysql -lmysqld -ldl  -L/opt/local/lib -lz -lm     -L/opt/local/lib/ -lssl -lcrypto]

This looks rather serious. Let's plug these values into our gem install command and see what happens:

$ sudo env ARCHFLAGS="-I/opt/local/include/mysql5/mysql  -pipe -fPIC    -D_P1003_1B_VISIBLE -DSIGNAL_WITH_VIO_CLOSE -DSIGNALS_DONT_BREAK_READ -DIGNORE_SIGHUP_SIGQUIT  -DDONT_DECLARE_CXA_PURE_VIRTUAL" gem install mysql -- --with-mysql-dir=/usr/local/mysql --with-mysql-lib=/opt/local/lib/mysql5/mysql --with-mysql-include=/opt/local/include/mysql5/mysql --with-mysql-config=/opt/local/bin/mysql_config5
Building native extensions.  This could take a while...
Successfully installed mysql-2.8.1
1 gem installed
Installing ri documentation for mysql-2.8.1...
Installing RDoc documentation for mysql-2.8.1...

Wow! Bingo! Bring on the beer!

Well there you go I hope this helps, or at least gives you some ideas, if you're stuck with Symbol not found: _mysql_init or extconf.rb failed when you can't get your mysql gem to install.