genksyms: fix syntax error for attribute before init-declarator

A longstanding issue with genksyms is that it has hidden syntax errors.

For example, genksyms fails to parse the following valid code:

    int x, __attribute__((__section__(".init.data")))y;

Here, only 'y' is annotated by the attribute, although I am not aware
of actual uses of this pattern in the kernel tree.

When a syntax error occurs, yyerror() is called. However,
error_with_pos() is a no-op unless the -w option is provided.

You can observe syntax errors by manually passing the -w option.

    $ echo 'int x, __attribute__((__section__(".init.data")))y;' | scripts/genksyms/genksyms -w
    <stdin>:1: syntax error

This commit allows attributes to be placed between a comma and
init_declarator.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Nicolas Schier <n.schier@avm.de>

Author: masahir0y

scripts/genksyms/parse.y

@@ -173,9 +173,9 @@ init_declarator_list:
 		  $$ = $1;
 		  dont_want_type_specifier = true;
 		}
-	| init_declarator_list ',' init_declarator
-		{ struct string_list *decl = *$3;
-		  *$3 = NULL;
+	| init_declarator_list ',' attribute_opt init_declarator
+		{ struct string_list *decl = *$4;
+		  *$4 = NULL;
 		  free_list(*$2, NULL);
 		  *$2 = decl_spec;
 
@@ -186,7 +186,7 @@ init_declarator_list:
 		  add_symbol(current_name,
 			     is_typedef ? SYM_TYPEDEF : SYM_NORMAL, decl, is_extern);
 		  current_name = NULL;
-		  $$ = $3;
+		  $$ = $4;
 		  dont_want_type_specifier = true;
 		}
 	;