[Issue 17851] htonl already defined in phobos64.lib

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=17851

--- Comment #1 from Heromyth <bitworld at qq.com> ---
It seems these functions have been defined in Ws2_32.lib, see
https://msdn.microsoft.com/en-us/library/windows/desktop/ms738556(v=vs.85).aspx

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