Não é possível instalar o gem mysql no Mac OS X

Eu instalei o servidor MySQL com o instalador dehttp://dev.mysql.com/downloads/mysql. Então, como explicado em vários guias, eu queria instalar o gem mysql com o seguinte comando.

sudo gem install mysql

Isso não está funcionando e fornece a seguinte saída.

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

        /Users/luzi/.rvm/rubies/ruby-1.9.3-p429/bin/ruby extconf.rb --with-mysql-dir=/usr/local/mysql/
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=/Users/luzi/.rvm/rubies/ruby-1.9.3-p429/bin/ruby
    --with-mysql-config
    --without-mysql-config
/Users/luzi/.rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/mkmf.rb:381:in `try_do': The compiler failed to generate an executable file. (RuntimeError)
You have to install development tools first.
    from /Users/luzi/.rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/mkmf.rb:461:in `try_link0'
    from /Users/luzi/.rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/mkmf.rb:476:in `try_link'
    from /Users/luzi/.rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/mkmf.rb:619:in `try_func'
    from /Users/luzi/.rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/mkmf.rb:894:in `block in have_func'
    from /Users/luzi/.rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/mkmf.rb:790:in `block in checking_for'
    from /Users/luzi/.rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/mkmf.rb:284:in `block (2 levels) in postpone'
    from /Users/luzi/.rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/mkmf.rb:254:in `open'
    from /Users/luzi/.rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/mkmf.rb:284:in `block in postpone'
    from /Users/luzi/.rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/mkmf.rb:254:in `open'
    from /Users/luzi/.rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/mkmf.rb:280:in `postpone'
    from /Users/luzi/.rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/mkmf.rb:789:in `checking_for'
    from /Users/luzi/.rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/mkmf.rb:893:in `have_func'
    from extconf.rb:45:in `<main>'


Gem files will remain installed in /Users/luzi/.rvm/gems/ruby-1.9.3-p429/gems/mysql-2.9.1 for inspection.
Results logged to /Users/luzi/.rvm/gems/ruby-1.9.3-p429/gems/mysql-2.9.1/ext/mysql_api/gem_make.out

Eu reinstalei o ruby ​​1.9.3 várias vezes. Os utilitários de linha de comando do XCode também estão instalados. Eu instalei o servidor mysql com homebrew, também (não trouxe nada).

Eu também tentei algumas opções para o comando acima, como--with-mysql-dir=/usr/local/mysql e--with-mysql-config=/usr/local/mysql/bin/mysql_config. Passando em bandeiras (sudo env ARCHFLAGS="-arch x86_64" gem install mysql) não ajudou nem.

ATUALIZAR:

Eu também tentei a gem mysql2, com o resultado do mesmo erro aparecendo, provavelmente porque a gem mysql2 é dependente da gem mysql.

ATUALIZAÇÃO 2:

Conteúdo demkmf.log:

"/opt/local/bin/gcc-apple-4.2 -o conftest -I/Users/luzi/.rvm/rubies/ruby-1.9.3-p429/include/ruby-1.9.1/x86_64-darwin12.4.0 -I/Users/luzi/.rvm/rubies/ruby-1.9.3-p429/include/ruby-1.9.1/ruby/backward -I/Users/luzi/.rvm/rubies/ruby-1.9.3-p429/include/ruby-1.9.1 -I. -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE   -I/opt/local/include -I/usr/local/mysql/include  -Wno-null-conversion -Os -g -fno-strict-aliasing -arch x86_64  -O3 -ggdb -Wall -Wextra -Wno-unused-parameter -Wno-parentheses -Wno-long-long -Wno-missing-field-initializers -Wpointer-arith -Wwrite-strings -Wdeclaration-after-statement -Wshorten-64-to-32 -Wimplicit-function-declaration  -fno-common -pipe conftest.c  -L. -L/Users/luzi/.rvm/rubies/ruby-1.9.3-p429/lib -L/opt/local/lib -L. -L/usr/local/lib -L/opt/local/lib     -L/usr/local/mysql/lib -lmysqlclient  -lruby.1.9.1  -lpthread -ldl -lobjc "
cc1: error: unrecognized command line option "-Wno-null-conversion"
checked program was:
/* begin */
1: #include "ruby.h"
2: 
3: int main(int argc, char **argv)
4: {
5:   return 0;
6: }
/* end */

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