Add initial support for native win32 platform
Should be built against MinGW, and please note that
only ss-local is ported due to lack win32 support of
libasyncns. And libev doesn't support IOCP but only
supports select
Fix cross-compiling issue by removing AC_FUNC_MALLOC
Merge pull request #16 from linusyang/udpmerge

Add support for native win32 platform