Initial Winlib

Designed to be license friendlier with apache2 than cygwin (which is
gpl) - these are posix wrappers that call into windows api for use with
facebook/folly and facebook/hhvm for windows builds

These are designed to build with MSVC 14 (CTP) and Mingw-w64

Contains two bundled libraries with some patches related to dl_info and
additional mmap apis