Problems installing mysql gem on Centos? Try installing the mysql development headers first

Was trying to install the mysql gem on a Centos linux server, but was having a problem. It was like:

> gem install mysql
Updating metadata for 6 gems from http://gems.rubyforge.org
......
complete
Building native extensions. This could take a while...
ERROR: Error installing mysql:
ERROR: Failed to build gem native extension.

/usr/bin/ruby extconf.rb install mysql
checking for mysql_query() in -lmysqlclient... no
checking for main() in -lm... yes
checking for mysql_query() in -lmysqlclient... no
checking for main() in -lz... no
checking for mysql_query() in -lmysqlclient... no
checking for main() in -lsocket... no
checking for mysql_query() in -lmysqlclient... no
checking for main() in -lnsl... yes
checking for mysql_query() in -lmysqlclient... no
*** 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=/usr/bin/ruby
--with-mysql-config
--without-mysql-config
--with-mysql-dir
--without-mysql-dir
--with-mysql-include
--without-mysql-include=${mysql-dir}/include
--with-mysql-lib
--without-mysql-lib=${mysql-dir}/lib
--with-mysqlclientlib
--without-mysqlclientlib
--with-mlib
--without-mlib
--with-mysqlclientlib
--without-mysqlclientlib
--with-zlib
--without-zlib
--with-mysqlclientlib
--without-mysqlclientlib
--with-socketlib
--without-socketlib
--with-mysqlclientlib
--without-mysqlclientlib
--with-nsllib
--without-nsllib
--with-mysqlclientlib
--without-mysqlclientlib


Gem files will remain installed in /usr/lib64/ruby/gems/1.8/gems/mysql-2.7 for inspection.
Results logged to /usr/lib64/ruby/gems/1.8/gems/mysql-2.7/gem_make.out

I managed to fix it by installing the mysql development headers first. We had already downloaded it onto the server, so instead of using yum, we used rpm -i to install it. Yum wouldn't have worked anyway, because we were using Mysql 5.1.22, which is not yet on the yum repository (only 5.0.45 is there).


rpm -i MySQL-devel-community-5.1.22-0.rhel5.x86_64.rpm

[root@cr1sescl01 mysql]# gem install mysql
Updating metadata for 32 gems from http://gems.rubyforge.org
................................
complete
Building native extensions. This could take a while...
Successfully installed mysql-2.7
1 gem installed