https://issues.dlang.org/show_bug.cgi?id=13751

          Issue ID: 13751
           Summary: WaitForMultipleObjects's first argument not use on
                    x86_64
           Product: D
           Version: D2
          Hardware: x86_64
                OS: Windows
            Status: NEW
          Severity: enhancement
          Priority: P1
         Component: druntime
          Assignee: nobody@puremagic.com
          Reporter: ILikeDub@163.com

if you compile the dfl Library to 64 bit,you will find error:

core.sys.windows.windows.WaitForMultipleObjects(uint nCount,void** lpHandles,....) is not callable using argument types(ulong,void**,...)

the 'WaitForMultipleObjects' Function is in dmd2/src/druntime/src/core/sys/windows/windows.d

the argument of first is dfl's value ,it come from a 'length' ,it's type is size_t,now it is 'ulong' on 64 bit.

So druntime must keep the same as  phobos for size_t.

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