Update os.h
Update os.h

Provide shared read access to log files under windows
godbyk/spdlog,COMBINE-lab/spdlog,simonhang/spdlog,GreatFruitOmsk/spdlog,icylord/spdlog,simonhang/spdlog,godbyk/spdlog,gregoire-astruc/spdlog,gnzlbg/spdlog,hunter-packages/spdlog,chenyu2202863/spdlog,ksophocleous/spdlog,GamePad64/spdlog,fcoulombe/spdlog,icylord/spdlog,ksophocleous/spdlog,hunter-packages/spdlog,mihadyuk/spdlog,mihadyuk/spdlog,GamePad64/spdlog,gnzlbg/spdlog,mihadyuk/spdlog,hunter-packages/spdlog,chenyu2202863/spdlog,godbyk/spdlog,GreatFruitOmsk/spdlog,gregoire-astruc/spdlog,COMBINE-lab/spdlog,icylord/spdlog,COMBINE-lab/spdlog,fcoulombe/spdlog