[parser] ignore _Nullable attribute

src/kernel_internals/parsing/clexer.mll

@@ -161,6 +161,7 @@ let init_lexicon _ =
          STATIC_ASSERT loc);
       ("__attribute__", fun loc -> ATTRIBUTE loc);
       ("__attribute", fun loc -> ATTRIBUTE loc);
+      ("_Nullable", fun loc -> NOP_ATTRIBUTE loc);
       ("__blockattribute__", fun _ -> BLOCKATTRIBUTE);
       ("__blockattribute", fun _ -> BLOCKATTRIBUTE);
       ("__asm__", fun loc -> ASM loc);

src/kernel_internals/parsing/cparser.mly

@@ -368,7 +368,7 @@ let in_ghost_block ?(battrs=[]) l =
 %token<Cabs.cabsloc> IF TRY EXCEPT FINALLY
 %token ELSE
 
-%token<Cabs.cabsloc> ATTRIBUTE INLINE NORETURN STATIC_ASSERT ASM TYPEOF FUNCTION__ PRETTY_FUNCTION__
+%token<Cabs.cabsloc> NOP_ATTRIBUTE ATTRIBUTE INLINE NORETURN STATIC_ASSERT ASM TYPEOF FUNCTION__ PRETTY_FUNCTION__
 %token LABEL__
 %token<Cabs.cabsloc> BUILTIN_VA_ARG
 %token BLOCKATTRIBUTE
@@ -1587,6 +1587,7 @@ attributes_with_asm:
 attribute_nocv:
     ATTRIBUTE LPAREN paren_attr_list RPAREN
                                         { ("__attribute__", $3), $1 }
+|   NOP_ATTRIBUTE                       { ("__attribute__", []), $1 }
 |   DECLSPEC paren_attr_list_ne         { ("__declspec", $2), $1 }
 |   MSATTR                              { (fst $1, []), snd $1 }
                                         /* ISO 6.7.3 */