bin/find-unneeded-includes: don't trip on BOX2D_HEADER in --sanitycheck

This is tricky because a header name is defined in a macro
and I had an exclusion for this external libs wrapper header.

But --sanitycheck does not see that, as it looks for presence of
exclusion list items.

Move the exclusion into the script, so that find-unneeded-includes
ignores it when checking the IWYU output and --sanitycheck does not
have to deal with this special rare case

Change-Id: I55d61630dd63a48d9b264df4b714dad999d1eacd
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/191827
Reviewed-by: Gabor Kelemen <gabor.kelemen.extern@allotropia.de>
Tested-by: Jenkins

bin/find-unneeded-includes

@@ -131,6 +131,8 @@ def ignoreRemoval(include, toAdd, absFileName, moduleRules, noexclude):
         return True
     if include == "libetonyek/libetonyek.h" and "libetonyek/EtonyekDocument.h" in toAdd:
         return True
+    if include == "box2d/box2d.h" and "box2d/b2_world.h" in toAdd:
+        return True
 
     noRemove = (
         # <https://www.openoffice.org/tools/CodingGuidelines.sxw> insists on not

slideshow/IwyuFilter_slideshow.yaml

@@ -11,9 +11,6 @@ excludelist:
     - config_lgpl.h
     # Wrapper for external lib
     - glm/gtc/type_ptr.hpp
-    slideshow/source/engine/box2dtools.cxx:
-    # Macro BOX2D_HEADER is resolved to this
-    - box2d/box2d.h
     slideshow/source/engine/opengl/Operation.cxx:
     # Wrapper for external lib
     - glm/gtc/matrix_transform.hpp