Silence a few compiler warnings from gcc on MinGW.

Most of these cast DWORD to int or unsigned int for printf type handling.
This is safe even on 64 bit architectures because a DWORD is always 32 bits.

In one case a variable is initialised to keep the compiler happy.

src/backend/port/win32/crashdump.c

@@ -135,7 +135,8 @@ crashDumpHandler(struct _EXCEPTION_POINTERS * pExceptionInfo)
 
 		systemTicks = GetTickCount();
 		snprintf(dumpPath, _MAX_PATH,
-			   "crashdumps\\postgres-pid%0i-%0i.mdmp", selfPid, systemTicks);
+				 "crashdumps\\postgres-pid%0i-%0i.mdmp", 
+				 (int) selfPid, (int) systemTicks);
 		dumpPath[_MAX_PATH - 1] = '\0';
 
 		dumpFile = CreateFile(dumpPath, GENERIC_WRITE, FILE_SHARE_WRITE,
@@ -143,8 +144,8 @@ crashDumpHandler(struct _EXCEPTION_POINTERS * pExceptionInfo)
 							  NULL);
 		if (dumpFile == INVALID_HANDLE_VALUE)
 		{
-			write_stderr("could not open crash dump file %s for writing: error code %d\n",
-						 dumpPath, GetLastError());
+			write_stderr("could not open crash dump file %s for writing: error code %u\n",
+						 dumpPath, (unsigned int) GetLastError());
 			return EXCEPTION_CONTINUE_SEARCH;
 		}
 
@@ -153,7 +154,7 @@ crashDumpHandler(struct _EXCEPTION_POINTERS * pExceptionInfo)
 			write_stderr("wrote crash dump to %s\n", dumpPath);
 		else
 			write_stderr("could not write crash dump to %s: error code %08x\n",
-						 dumpPath, GetLastError());
+						 dumpPath, (unsigned int) GetLastError());
 
 		CloseHandle(dumpFile);
 	}

src/backend/port/win32_latch.c

@@ -94,7 +94,7 @@ WaitLatchOrSocket(volatile Latch *latch, SOCKET sock, bool forRead,
 	DWORD		rc;
 	HANDLE		events[3];
 	HANDLE		latchevent;
-	HANDLE		sockevent;
+	HANDLE		sockevent = WSA_INVALID_EVENT; /* silence compiler */
 	int			numevents;
 	int			result = 0;
 
@@ -161,7 +161,7 @@ WaitLatchOrSocket(volatile Latch *latch, SOCKET sock, bool forRead,
 			break;
 		}
 		else if (rc != WAIT_OBJECT_0)
-			elog(ERROR, "unexpected return code from WaitForMultipleObjects(): %d", rc);
+			elog(ERROR, "unexpected return code from WaitForMultipleObjects(): %d", (int) rc);
 	}
 
 	/* Clean up the handle we created for the socket */