No puedo instalar la gema mysql2 en mi sistema Windows7 x64. Intenté usar las versiones de 32 bits y 64 bits del servidor MySQL, pero ninguna me ayudó más.

Instalé Ruby 1.8, el kit de desarrollo y la plataforma Rails. Incluso instalé minGW para permitir la compilación de cosas en C ++ / C. MySQL Server se instaló en la ubicación predeterminada.

Al ejecutar el comando:

C:\Users\Arne>gem install mysql2 -- --with-mysql-include="C:\Program Files (x86)\MySQL\MySQL Server 5.1\include" --with-mysql-lib="C:\Program Files (x86)\MySQL\MySQL Server 5.1\lib\"

Recibo el siguiente resultado de la consola:

Temporarily enhancing PATH to include DevKit...
Building native extensions.  This could take a while...
*** 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
        --without-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=C:/Ruby/bin/ruby
        --with-mysql-dir
        --without-mysql-dir
        --with-mysql-include=${mysql-dir}/include
        --with-mysql-lib=${mysql-dir}/lib
        --with-libmysqllib
        --without-libmysqllib
ERROR:  Error installing mysql2:
        ERROR: Failed to build gem native extension.

        C:/Ruby/bin/ruby.exe extconf.rb --with-mysql-include=C:\Program Files (x
86)\MySQL\MySQL Server 5.1\include --with-mysql-lib=C:\Program Files (x86)\MySQL
\MySQL Server 5.1\lib"
checking for rb_thread_blocking_region()... no
checking for main() in -llibmysql... no


Gem files will remain installed in C:/Ruby/lib/ruby/gems/1.8/gems/mysql2-0.3.2 f
or inspection.
Results logged to C:/Ruby/lib/ruby/gems/1.8/gems/mysql2-0.3.2/ext/mysql2/gem_mak
e.out

La salida de mi entorno según Rubygems es:

C:\Users\Arne>gem env
RubyGems Environment:
  - RUBYGEMS VERSION: 1.7.2
  - RUBY VERSION: 1.8.7 (2011-02-18 patchlevel 334) [i386-mingw32]
  - INSTALLATION DIRECTORY: C:/Ruby/lib/ruby/gems/1.8
  - RUBY EXECUTABLE: C:/Ruby/bin/ruby.exe
  - EXECUTABLE DIRECTORY: C:/Ruby/bin
  - RUBYGEMS PLATFORMS:
    - ruby
    - x86-mingw32
  - GEM PATHS:
     - C:/Ruby/lib/ruby/gems/1.8
     - C:/Users/Arne/.gem/ruby/1.8
  - GEM CONFIGURATION:
     - :update_sources => true
     - :verbose => true
     - :benchmark => false
     - :backtrace => false
     - :bulk_threshold => 1000
  - REMOTE SOURCES:
     - http://rubygems.org/

Las siguientes gemas también se han instalado en el sistema:

C:\Users\Arne>gem list --local

*** LOCAL GEMS ***

abstract (1.0.0)
actionmailer (3.0.7)
actionpack (3.0.7)
activemodel (3.0.7)
activerecord (3.0.7)
activeresource (3.0.7)
activesupport (3.0.7)
arel (2.0.9)
builder (3.0.0, 2.1.2)
bundler (1.0.12)
erubis (2.7.0, 2.6.6)
fastthread (1.0.7)
i18n (0.5.0)
mail (2.3.0, 2.2.18)
mime-types (1.16)
mysql (2.8.1 x86-mingw32)
polyglot (0.3.1)
rack (1.2.2)
rack-mount (0.7.2, 0.6.14)
rack-test (0.5.7)
rails (3.0.7)
railties (3.0.7)
rake (0.8.7)
rdoc (3.5.3, 2.5.11)
rdoc-data (2.5.3)
rubygems-update (1.7.2)
thor (0.14.6)
treetop (1.4.9)
tzinfo (0.3.27, 0.3.26)

No sé qué falta o qué está mal, pero los archivos de salida señalados por el script contienen los siguientes datos:

mkmf.log:

have_func: checking for rb_thread_blocking_region()... -------------------- no

"gcc -o conftest -I. -IC:/Ruby/lib/ruby/1.8/i386-mingw32 -I.    -g -O2 -DFD_SETSIZE=256    conftest.c  -L. -LC:/Ruby/lib -L.      -lmsvcrt-ruby18-static  -lshell32 -lws2_32  "
conftest.c: In function 't':
conftest.c:7:53: error: 'rb_thread_blocking_region' undeclared (first use in this function)
conftest.c:7:53: note: each undeclared identifier is reported only once for each function it appears in
checked program was:
/* begin */
1: #include <ws2tcpip.h>
2: #include <winsock2.h>
3: #include <windows.h>
4: 
5: /*top*/
6: int main() { return 0; }
7: int t() { void ((*volatile p)()); p = (void ((*)()))rb_thread_blocking_region; return 0; }
/* end */

"gcc -o conftest -I. -IC:/Ruby/lib/ruby/1.8/i386-mingw32 -I.    -g -O2 -DFD_SETSIZE=256    conftest.c  -L. -LC:/Ruby/lib -L.      -lmsvcrt-ruby18-static  -lshell32 -lws2_32  "
C:\Users\Arne\AppData\Local\Temp\ccCicaNu.o: In function `t':
C:\Ruby\lib\ruby\gems\1.8\gems\mysql2-0.3.2\ext\mysql2/conftest.c:3: undefined reference to `rb_thread_blocking_region'
collect2: ld returned 1 exit status
checked program was:
/* begin */
1: /*top*/
2: int main() { return 0; }
3: int t() { rb_thread_blocking_region(); return 0; }
/* end */

--------------------

have_library: checking for main() in -llibmysql... -------------------- no

"gcc -o conftest -I. -IC:/Ruby/lib/ruby/1.8/i386-mingw32 -I. -IC:\Program    -g -O2 -DFD_SETSIZE=256    conftest.c  -L. -LC:/Ruby/lib -LC:\Program -L.      -lmsvcrt-ruby18-static -llibmysql  -lshell32 -lws2_32  "
c:/mingw/bin/../lib/gcc/mingw32/4.5.2/../../../../mingw32/bin/ld.exe: cannot find -llibmysql
collect2: ld returned 1 exit status
checked program was:
/* begin */
1: #include <ws2tcpip.h>
2: #include <winsock2.h>
3: #include <windows.h>
4: 
5: /*top*/
6: int main() { return 0; }
7: int t() { void ((*volatile p)()); p = (void ((*)()))main; return 0; }
/* end */

"gcc -o conftest -I. -IC:/Ruby/lib/ruby/1.8/i386-mingw32 -I. -IC:\Program    -g -O2 -DFD_SETSIZE=256    conftest.c  -L. -LC:/Ruby/lib -LC:\Program -L.      -lmsvcrt-ruby18-static -llibmysql  -lshell32 -lws2_32  "
c:/mingw/bin/../lib/gcc/mingw32/4.5.2/../../../../mingw32/bin/ld.exe: cannot find -llibmysql
collect2: ld returned 1 exit status
checked program was:
/* begin */
1: /*top*/
2: int main() { return 0; }
3: int t() { main(); return 0; }
/* end */

--------------------

gem_make.out:

C:/Ruby/bin/ruby.exe extconf.rb --with-mysql-include=C:\Program Files (x86)\MySQL\MySQL Server 5.1\include --with-mysql-lib=C:\Program Files (x86)\MySQL\MySQL Server 5.1\lib"
checking for rb_thread_blocking_region()... no
checking for main() in -llibmysql... no

Espero que alguien pueda señalar lo que estoy haciendo mal o lo que realmente falta en mi sistema de desarrollo para que esta gema se instale y funcione correctamente.