user32: Return DMLERR_MEMORY_ERROR instead of posting an ACK when fAckReq is returned by the server for WM_DDE_DATA.

iphlpapi: UINT and DWORD are now equivalent, even in 64-bit compiles, so remove unnecessary complication.

S24_LE is aligned with 4 bytes instead of the expected 3.

The memory is allocated with HEAP_ZERO_MEMORY.

user32: Fix the HRAWINPUT definition and the GetRawInputData() prototype. Update win32.api to fix the winapi_check warnings.