merge revision(s) 4adb2d655dcd54b28366b4d17e86b21e2b622cd1: [Backport #16738]

Make RbConfig::CONFIG values mutable [Bug #16738]

	As `RbConfig.expand` modifies the argument and involved `CONFIG`
	values, its values should be mutable.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_5@67872 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/test_rbconfig.rb

@@ -51,4 +51,13 @@ class TestRbConfig < Test::Unit::TestCase
       assert_match(/\$\(sitearch|\$\(rubysitearchprefix\)/, val, "#{key} #{bug7823}")
     end
   end
+
+  if /darwin/ =~ RUBY_PLATFORM
+    def test_sdkroot
+      assert_separately([{"SDKROOT" => "$(prefix)/SDKRoot"}], "#{<<~"begin;"}\n#{<<~'end;'}")
+      begin;
+        assert_equal RbConfig::CONFIG["prefix"]+"/SDKRoot", RbConfig::CONFIG["SDKROOT"]
+      end;
+    end
+  end
 end

tool/mkconfig.rb

@@ -245,7 +245,7 @@ print <<EOS if $unicode_version
   CONFIG["UNICODE_VERSION"] = #{$unicode_version.dump}
 EOS
 print <<EOS if /darwin/ =~ arch
-  CONFIG["SDKROOT"] = ENV["SDKROOT"] || "" # don't run xcrun everytime, usually useless.
+  CONFIG["SDKROOT"] = "\#{ENV['SDKROOT']}" # don't run xcrun every time, usually useless.
 EOS
 print <<EOS
   CONFIG["archdir"] = "$(rubyarchdir)"

version.h

@@ -1,6 +1,6 @@
 #define RUBY_VERSION "2.5.8"
 #define RUBY_RELEASE_DATE "2020-03-31"
-#define RUBY_PATCHLEVEL 221
+#define RUBY_PATCHLEVEL 222
 
 #define RUBY_RELEASE_YEAR 2020
 #define RUBY_RELEASE_MONTH 3