There's no point in having separate types depending on C dialect
when using bitfields, "unsigned int" bitfields are bitfields
anywhere.

Note: we also have test_memsize in test_time.rb in case
users of other platforms want to enable size assertions
if they don't trust their compiler.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@61870 b2dd03c8-39d4-4d8f-98ff-823fe69b080e