Use DWORD instead of unsigned long in wxFileSystemWatcher wxMSW code.

These two types are not the same in 64 bit Cygwin builds, so fix the build by
just using DWORD everywhere.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@76506 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/fswatcher.cpp

@@ -221,7 +221,7 @@ wxThread::ExitCode wxIOCPThread::Entry()
 //         true otherwise
 bool wxIOCPThread::ReadEvents()
 {
-    unsigned long count = 0;
+    DWORD count = 0;
     wxFSWatchEntryMSW* watch = NULL;
     OVERLAPPED* overlapped = NULL;
     switch ( m_iocp->GetStatus(&count, &watch, &overlapped) )