Rename Ruby native ext

pkgs/ruby/Rakefile

@@ -54,7 +54,7 @@ end
 
 begin
   require 'rake/extensiontask'
-  Rake::ExtensionTask.new 'libkernaux' do |ext|
+  Rake::ExtensionTask.new 'default' do |ext|
     ext.lib_dir = 'lib/kernaux'
   end
 rescue LoadError

pkgs/ruby/ext/default/extconf.rb

@@ -2,4 +2,4 @@
 
 require 'mkmf'
 
-create_makefile 'kernaux/libkernaux'
+create_makefile 'kernaux/default'

pkgs/ruby/ext/default/main.c

@@ -1,5 +1,5 @@
 #include <ruby.h>
 
-void Init_libkernaux()
+void Init_default()
 {
 }

pkgs/ruby/kernaux.gemspec

@@ -37,7 +37,7 @@ Gem::Specification.new do |spec|
 
   spec.executables = spec.files.grep(%r{\Aexe/}) { |f| File.basename f }
 
-  spec.extensions << 'ext/libkernaux/extconf.rb'
+  spec.extensions << 'ext/default/extconf.rb'
 
   spec.add_development_dependency 'bundler',             '~> 2.2'
   spec.add_development_dependency 'pry',                 '~> 0.14'

pkgs/ruby/lib/kernaux.rb

@@ -9,4 +9,4 @@ module KernAux
 end
 
 # Native extension
-require_relative 'kernaux/libkernaux'
+require_relative 'kernaux/default'