kernel32: Fix some 64-bit issues in GlobalSize().

dlls/kernel32/heap.c

@@ -808,7 +808,7 @@ HGLOBAL WINAPI GlobalFree(HGLOBAL hmem)
  */
 SIZE_T WINAPI GlobalSize(HGLOBAL hmem)
 {
-   DWORD                retval;
+   SIZE_T               retval;
    PGLOBAL32_INTERN     pintern;
 
    if (!((ULONG_PTR)hmem >> 16))
@@ -821,10 +821,10 @@ SIZE_T WINAPI GlobalSize(HGLOBAL hmem)
    {
       retval=HeapSize(GetProcessHeap(), 0, hmem);
 
-      if (retval == (DWORD)-1) /* It might be a GMEM_MOVEABLE data pointer */
+      if (retval == ~0ul) /* It might be a GMEM_MOVEABLE data pointer */
       {
-          retval = HeapSize(GetProcessHeap(), 0, (char*)(hmem) - HGLOBAL_STORAGE);
-          if (retval != (DWORD)-1) retval -= HGLOBAL_STORAGE;
+          retval = HeapSize(GetProcessHeap(), 0, (char*)hmem - HGLOBAL_STORAGE);
+          if (retval != ~0ul) retval -= HGLOBAL_STORAGE;
       }
    }
    else
@@ -838,9 +838,8 @@ SIZE_T WINAPI GlobalSize(HGLOBAL hmem)
              retval = 0;
          else
          {
-             retval = HeapSize(GetProcessHeap(), 0,
-                         (char *)(pintern->Pointer) - HGLOBAL_STORAGE );
-             if (retval != (DWORD)-1) retval -= HGLOBAL_STORAGE;
+             retval = HeapSize(GetProcessHeap(), 0, (char *)pintern->Pointer - HGLOBAL_STORAGE );
+             if (retval != ~0ul) retval -= HGLOBAL_STORAGE;
          }
       }
       else
@@ -851,8 +850,7 @@ SIZE_T WINAPI GlobalSize(HGLOBAL hmem)
       }
       RtlUnlockHeap(GetProcessHeap());
    }
-   /* HeapSize returns 0xffffffff on failure */
-   if (retval == 0xffffffff) retval = 0;
+   if (retval == ~0ul) retval = 0;
    return retval;
 }