[rubygems/rubygems] Keep Gem.install_extension_in_lib for compatibility

https://github.com/rubygems/rubygems/commit/b2bf239147

lib/rubygems/config_file.rb

@@ -47,6 +47,7 @@ class Gem::ConfigFile
   DEFAULT_CONCURRENT_DOWNLOADS = 8
   DEFAULT_CERT_EXPIRATION_LENGTH_DAYS = 365
   DEFAULT_IPV4_FALLBACK_ENABLED = false
+  # TODO: Use false as default value for this option in RubyGems 4.0
   DEFAULT_INSTALL_EXTENSION_IN_LIB = true
 
   ##

lib/rubygems/defaults.rb

@@ -247,6 +247,13 @@ module Gem
     false
   end
 
+  ##
+  # Install extensions into lib as well as into the extension directory.
+
+  def self.install_extension_in_lib # :nodoc:
+    Gem.configuration.install_extension_in_lib
+  end
+
   ##
   # Directory where vendor gems are installed.
 

lib/rubygems/ext/cargo_builder.rb

@@ -47,7 +47,7 @@ class Gem::Ext::CargoBuilder < Gem::Ext::Builder
 
       nesting = extension_nesting(extension)
 
-      if Gem.configuration.install_extension_in_lib && lib_dir
+      if Gem.install_extension_in_lib && lib_dir
         nested_lib_dir = File.join(lib_dir, nesting)
         FileUtils.mkdir_p nested_lib_dir
         FileUtils.cp_r dlext_path, nested_lib_dir, remove_destination: true

lib/rubygems/ext/ext_conf_builder.rb

@@ -43,7 +43,7 @@ class Gem::Ext::ExtConfBuilder < Gem::Ext::Builder
 
       full_tmp_dest = File.join(extension_dir, tmp_dest_relative)
 
-      if Gem.configuration.install_extension_in_lib && lib_dir
+      if Gem.install_extension_in_lib && lib_dir
         FileUtils.mkdir_p lib_dir
         entries = Dir.entries(full_tmp_dest) - %w[. ..]
         entries = entries.map {|entry| File.join full_tmp_dest, entry }