Heap errors in 64-bit Windows

[uecasm]

If I build slpd for 64-bit Windows (using the vs2010 solution upgraded to vs2017) it frequently crashes in malloc/free, sometimes when an app uses the API to register, other times when it unregisters (or terminates without explicitly unregistering), but pretty much always one or the other. Occasionally the actual crash is inside select() slightly after one of these events instead.

I haven't been able to trace it further than this as for some inexplicable reason VS is reporting that the PDB file is not compatible and won't give me any symbols for slpd itself. But I did try some older trees as well and the behaviour is the same at least as far back as 2011 when the vs2010 solution was first added.

The crashes are the "heap has been corrupted" type (RtlpLogHeapFailure).

The 32-bit build appears to work as expected.

[uecasm]

I still haven't been able to trace it down to anything specific, but assuming it works on 64-bit Linux then most likely there's some code somewhere assuming that sizeof(long) == sizeof(size_t) == sizeof(void*), which is true in Linux but not in Windows.

[urbasus]

Possibly related: #10