Gethostbyname on windows

Summary: use gethostbyname not gethostbyname_r on windows and add notes on windows oddnesses

Reviewed By: @sgolemon

Differential Revision: D1481313
Windows apis to retrieve name of symbol

Summary: Use apis available in dbghelp (available on all windows systems in many versions)
This uses only basic api calls so should be available no matter the version

Reviewed By: @sgolemon

Differential Revision: D1481204