return NULL from the functions returning a pointer, not FALSE (patch 544557)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@15158 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/dib.cpp

@@ -659,7 +659,7 @@ HPALETTE wxMakeDIBPalette(LPBITMAPINFOHEADER lpInfo)
         npPal = (LPLOGPALETTE)malloc(sizeof(LOGPALETTE) +
                                 (WORD)lpInfo->biClrUsed * sizeof(PALETTEENTRY));
         if (!npPal)
-            return(FALSE);
+            return NULL;
 
         npPal->palVersion = 0x300;
         npPal->palNumEntries = (WORD)lpInfo->biClrUsed;