Avoid capturing local variables referencing the pre-initialization home in blocks

(cherry picked from commit 97d4413)

Author: eregon

src/main/ruby/truffleruby/core/post.rb

@@ -105,16 +105,18 @@ def p(*a)
   ARGV.concat(Truffle::Boot.original_argv)
 end
 
-ruby_home = Truffle::Boot.ruby_home
-if ruby_home
-  # Does not exist but it's used by rubygems to determine index where to insert gem lib directories, as a result
-  # paths supplied by -I will stay before gem lib directories. See Gem.load_path_insert_index in rubygems.rb.
-  # Must be kept in sync with the value of RbConfig::CONFIG['sitelibdir'].
-  $LOAD_PATH.push "#{ruby_home}/lib/ruby/site_ruby/#{RUBY_ENGINE_VERSION}"
-
-  $LOAD_PATH.push "#{ruby_home}/lib/truffle"
-  $LOAD_PATH.push "#{ruby_home}/lib/mri"
-  $LOAD_PATH.push "#{ruby_home}/lib/json/lib"
+yield_self do # Avoid capturing ruby_home in the at_exit and delay blocks
+  ruby_home = Truffle::Boot.ruby_home
+  if ruby_home
+    # Does not exist but it's used by rubygems to determine index where to insert gem lib directories, as a result
+    # paths supplied by -I will stay before gem lib directories. See Gem.load_path_insert_index in rubygems.rb.
+    # Must be kept in sync with the value of RbConfig::CONFIG['sitelibdir'].
+    $LOAD_PATH.push "#{ruby_home}/lib/ruby/site_ruby/#{RUBY_ENGINE_VERSION}"
+
+    $LOAD_PATH.push "#{ruby_home}/lib/truffle"
+    $LOAD_PATH.push "#{ruby_home}/lib/mri"
+    $LOAD_PATH.push "#{ruby_home}/lib/json/lib"
+  end
 end
 
 Truffle::Boot.delay do

src/main/ruby/truffleruby/post-boot/post-boot.rb

@@ -83,7 +83,7 @@
         end
       end
     end
-    old_home = nil
+    old_home = nil # Avoid capturing the old home in the blocks below
 
     Truffle::Boot.delay do
       new_home = Truffle::Boot.ruby_home