win32/file.c: share functions with win32.c
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47117 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
win32/file.c: share functions with win32.c
use functions defined in win32/win32.c.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47117 b2dd03c8-39d4-4d8f-98ff-823fe69b080e