kernel32: Fix some compilation warnings in 64-bit mode.

dlls/kernel32/kernel16_private.h

@@ -168,7 +168,7 @@ extern THHOOK *pThhook;
     (((offset)+(size) <= pModule->mapping_size) ? \
      (memcpy( buffer, (const char *)pModule->mapping + (offset), (size) ), TRUE) : FALSE)
 
-#define CURRENT_STACK16 ((STACK16FRAME*)MapSL((SEGPTR)NtCurrentTeb()->WOW32Reserved))
+#define CURRENT_STACK16 ((STACK16FRAME*)MapSL(PtrToUlong(NtCurrentTeb()->WOW32Reserved)))
 #define CURRENT_DS      (CURRENT_STACK16->ds)
 
 /* push bytes on the 16-bit stack of a thread; return a segptr to the first pushed byte */

dlls/kernel32/selector.c

@@ -482,7 +482,7 @@ SEGPTR WINAPI MapLS( LPCVOID ptr )
 
     if (!HIWORD(ptr)) return (SEGPTR)LOWORD(ptr);
 
-    base = (const char *)ptr - ((unsigned int)ptr & 0x7fff);
+    base = (const char *)ptr - ((ULONG_PTR)ptr & 0x7fff);
     HeapLock( GetProcessHeap() );
     for (entry = first_entry; entry; entry = entry->next)
     {