* ext/fiddle/closure.c (USE_FFI_CLOSURE_ALLOC): add missing case:
  RUBY_LIBFFI_MODVERSION is not defined (usually on Windows).

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40225 b2dd03c8-39d4-4d8f-98ff-823fe69b080e