yacc.c raises warnings with `-std=c89 -pedantic`

[GitMensch]

The reason is

bison/data/skeletons/yacc.c

Lines 2008 to 2009 in 25b3d0e

	yypcontext_t yyctx
	= {]b4_push_if([[yyps]], [[yyssp]b4_lac_if([[, yyesa, &yyes, &yyes_capacity]])])[, yytoken]b4_locations_if([[, &yylloc]])[};

which leads to a generation of

        yypcontext_t yyctx
          = {yyssp, yytoken};
        char const *yymsgp = YY_("syntax error");
        int yysyntax_error_status;
        yysyntax_error_status = yysyntax_error (&yymsg_alloc, &yymsg, &yyctx);

and therefore raises

parser.c:24521:14: warning: initializer element is not computable at load time [-Wpedantic]
24521 |           = {yyssp, yytoken};
      |              ^~~~~
parser.c:24521:21: warning: initializer element is not computable at load time [-Wpedantic]
24521 |           = {yyssp, yytoken};
      |                     ^~~~~~~

Changing the generated code as follows:

        yypcontext_t yyctx;
        char const *yymsgp = YY_("syntax error");
        int yysyntax_error_status;
        yysyntax_error_status = yysyntax_error (&yymsg_alloc, &yymsg, &yyctx);
        yyctx.yyssp = yyssp;
        yyctx.yytoken = yytoken;
        yysyntax_error_status = yysyntax_error (&yymsg_alloc, &yymsg, &yyctx);

fixes the code, but sadly that is not easily replaced by defining some macros.