Fix for homebrew 5.1.4

[sw17ch]

I noticed that RLua fails to install with the current version of Lua on Homebrew (5.1.4). Following is the error I get when trying to install. Several variations of the options also failed.

$ gem install rlua -- --with-lua5.1-lib=/usr/local/Cellar/lua/5.1.4/lib/ --with-opt-include=/usr/local/Cellar/lua/5.1.4/include/
Building native extensions.  This could take a while...
ERROR:  Error installing rlua:
    ERROR: Failed to build gem native extension.

        /Users/me/.rvm/rubies/ruby-1.9.3-p194/bin/ruby extconf.rb --with-lua5.1-lib=/usr/local/Cellar/lua/5.1.4/lib/ --with-opt-include=/usr/local/Cellar/lua/5.1.4/include/
checking for luaL_newstate() in -llua5.1... 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
    --with-opt-include=${opt-dir}/include
    --with-opt-lib
    --without-opt-lib=${opt-dir}/lib
    --with-make-prog
    --without-make-prog
    --srcdir=.
    --curdir
    --ruby=/Users/me/.rvm/rubies/ruby-1.9.3-p194/bin/ruby
    --with-lua5.1-dir
    --without-lua5.1-dir
    --with-lua5.1-include
    --without-lua5.1-include=${lua5.1-dir}/include
    --with-lua5.1-lib=${lua5.1-dir}/lib
    --with-lua5.1lib
    --without-lua5.1lib
 extconf failure: need liblua5.1

Gem files will remain installed in /Users/me/.rvm/gems/ruby-1.9.3-p194/gems/rlua-1.0 for inspection.
Results logged to /Users/me/.rvm/gems/ruby-1.9.3-p194/gems/rlua-1.0/ext/gem_make.out

These commits do a few things, but mainly:

1. Search for a library that includes a . before the version number in extconf.rb
2. #include <lua.h> instead of #include <lua5.1/lua.h>.

I'm not sure if #2 above is preferable. After making the changes in this pull request, running the following command manages to install the gem:

$ rake gem && gem install pkg/rlua-1.1.rc.1.gem -- --with-lua5.1-lib=/usr/local/Cellar/lua/5.1.4/lib --with-lua5.1-include=/usr/local/Cellar/lua/5.1.4/include/rake/gempackagetask is deprecated.  Use rubygems/package_task instead
WARNING: 'require 'rake/rdoctask'' is deprecated.  Please use 'require 'rdoc/task' (in RDoc 2.4.2+)' instead.
    at /Users/johnvanenk/.rvm/gems/ruby-1.9.3-p194/gems/rake-0.9.2.2/lib/rake/rdoctask.rb
mkdir -p pkg
rm -f pkg/rlua-1.1.rc.1/ext/rlua.c
ln ext/rlua.c pkg/rlua-1.1.rc.1/ext/rlua.c
rm -f pkg/rlua-1.1.rc.1/lib/rlua.rb
ln lib/rlua.rb pkg/rlua-1.1.rc.1/lib/rlua.rb
rm -f pkg/rlua-1.1.rc.1/LICENSE.rdoc
ln LICENSE.rdoc pkg/rlua-1.1.rc.1/LICENSE.rdoc
rm -f pkg/rlua-1.1.rc.1/README.rdoc
ln README.rdoc pkg/rlua-1.1.rc.1/README.rdoc
rm -f pkg/rlua-1.1.rc.1/TODO.rdoc
ln TODO.rdoc pkg/rlua-1.1.rc.1/TODO.rdoc
rm -f pkg/rlua-1.1.rc.1/ext/extconf.rb
ln ext/extconf.rb pkg/rlua-1.1.rc.1/ext/extconf.rb
cd pkg/rlua-1.1.rc.1
mv rlua-1.1.rc.1.gem ..
cd -
Building native extensions.  This could take a while...
Successfully installed rlua-1.1.rc.1
1 gem installed
Installing ri documentation for rlua-1.1.rc.1...
Installing RDoc documentation for rlua-1.1.rc.1...

[whitequark]

The pull request seems to work fine on Debian. I'll add a bit more stuff and release a new version of gem.

[whitequark]

By the way, I noticed that rlua is licensed under LGPL3, for historical reasons. I'm going to relicense it under MIT. Do you allow me to redistribute your contribution under that license, too?

[sw17ch]

Yes. Absolutely.

[sw17ch]

The beta gem fails to install on windows, but fails silently:

C:\Users\Administrator>gem install rlua -v 1.1.beta1
Successfully installed rlua-1.1.beta1
1 gem installed
Installing ri documentation for rlua-1.1.beta1...
Installing RDoc documentation for rlua-1.1.beta1...

C:\Users\Administrator>pry
[1] pry(main)> require 'rlua'
LoadError: cannot load such file -- rlua.so
from C:/Rubies/Ruby193/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb:36:in
 `require'
[2] pry(main)>

I haven't had a chance to do too much more investigation, but we noticed that the log file somehow fails to find the newstate symbol (which is a problem in and of itself). More importantly, it appears that if the checks/compilation fails, the gem doesn't fail to install.

[whitequark]

Hmm, not surprising -- it was never supposed to work on Windows. I don't have a Windows system anyway, so you're on your own. I guess that you just don't have Lua headers/libs installed.