Fix misuses of NULL across Windows-only code

...which defines NULL as a plain 0 integer literal instead of the GNU __null
extension, so clang-cl's -Wnull-conversion cannot kick in.  These findings are
from an experimental build done with clang-cl and a modified

> --- a/clang/lib/Headers/stddef.h
> +++ b/clang/lib/Headers/stddef.h
> @@ -83,6 +83,10 @@ typedef __WCHAR_TYPE__ wchar_t;
>  #  if !defined(__MINGW32__) && !defined(_MSC_VER)
>  #    define NULL __null
>  #  else
> -#    define NULL 0
> +#    if __cplusplus >= 201103L
> +#      define NULL nullptr
> +#    else
> +#      define NULL 0
> +#    endif
>  #  endif
>  #else
>  #  define NULL ((void*)0)

However, that build also ran into lots of places where 3rd-party code in
external/ and Windows system headers caused issues when NULL is nullptr (which
I worked around with various hacky patches for that build), so this is
unfortunately not something that can easily be enabled generally.

Change-Id: I10674464498a9bc63578d9e6cc32ddde23ab4f30
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/124419
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/winaccessibility/source/service/AccObjectManagerAgent.cxx b/winaccessibility/source/service/AccObjectManagerAgent.cxx
index ab909d495398..62d58f384f17 100644
--- a/winaccessibility/source/service/AccObjectManagerAgent.cxx
+++ b/winaccessibility/source/service/AccObjectManagerAgent.cxx
@@ -376,7 +376,7 @@ bool AccObjectManagerAgent::IsTopWinAcc(XAccessible* pXAcc)
     {
         return pWinManager->IsTopWinAcc( pXAcc );
     }
-    return NULL;
+    return false;
 }
 
 bool AccObjectManagerAgent::IsStateManageDescendant(XAccessible* pXAcc)