You tried to install mysql gem on linux:
$ gem install mysql
Building native extensions. This could take a while...
ERROR: Error installing mysql:
ERROR: Failed to build gem native extension.
/home/t/ruby-1.9.2-p136-1/bin/ruby extconf.rb
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
--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=/home/t/ruby-1.9.2-p136-1/bin/ruby
--with-mysql-config
--without-mysql-config
/home/t/ruby-1.9.2-p136-1/lib/ruby/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 /home/t/ruby-1.9.2-p136-1/lib/ruby/1.9.1/mkmf.rb:435:in `try_link0'
from /home/t/ruby-1.9.2-p136-1/lib/ruby/1.9.1/mkmf.rb:440:in `try_link'
from /home/t/ruby-1.9.2-p136-1/lib/ruby/1.9.1/mkmf.rb:552:in `try_func'
from /home/t/ruby-1.9.2-p136-1/lib/ruby/1.9.1/mkmf.rb:797:in `block in have_func'
from /home/t/ruby-1.9.2-p136-1/lib/ruby/1.9.1/mkmf.rb:693:in `block in checking_for'
from /home/t/ruby-1.9.2-p136-1/lib/ruby/1.9.1/mkmf.rb:280:in `block (2 levels) in postpone'
from /home/t/ruby-1.9.2-p136-1/lib/ruby/1.9.1/mkmf.rb:254:in `open'
from /home/t/ruby-1.9.2-p136-1/lib/ruby/1.9.1/mkmf.rb:280:in `block in postpone'
from /home/t/ruby-1.9.2-p136-1/lib/ruby/1.9.1/mkmf.rb:254:in `open'
from /home/t/ruby-1.9.2-p136-1/lib/ruby/1.9.1/mkmf.rb:276:in `postpone'
from /home/t/ruby-1.9.2-p136-1/lib/ruby/1.9.1/mkmf.rb:692:in `checking_for'
from /home/t/ruby-1.9.2-p136-1/lib/ruby/1.9.1/mkmf.rb:796:in `have_func'
from extconf.rb:50:in `<main>'
Gem files will remain installed in /home/t/ruby-1.9.2-p136-1/lib/ruby/gems/1.9.1/gems/mysql-2.8.1 for inspection.
Results logged to /home/t/ruby-1.9.2-p136-1/lib/ruby/gems/1.9.1/gems/mysql-2.8.1/ext/mysql_api/gem_make.out
You need to check mkmf.log which is in the same folder as gem_make.out is in. In my case, mkmf.log is in /home/t/ruby-1.9.2-p136-1/lib/ruby/gems/1.9.1/gems/mysql-2.8.1/ext/mysql_api/
Read mkmf.log, if you see something similar to below:
/usr/bin/ld: skipping incompatible /usr/lib/libz.so when searching for -lz
/usr/bin/ld: skipping incompatible /usr/lib/libz.a when searching for -lz
/usr/bin/ld: cannot find -lz
collect2: ld returned 1 exit status
It means you have an incompatible zlib-devel binary. In case, the 32-bit zlib-devel is installed, but not the 64 bits. Run following command to fix it:
yum erase zlib-devel
yum install zlib-devel
