fix for reading PgfExpr with a double literal

src/runtime/c/pgf/expr.c

@@ -494,7 +494,9 @@ pgf_expr_parser_term(PgfExprParser* parser)
 	case PGF_TOKEN_FLT: {
 		char* str = 
 			gu_buf_data(parser->token_value);
-		double d = atof(str);
+		double d;
+		if (!gu_string_to_double(str,&d))
+			return gu_null_variant;
 		pgf_expr_parser_token(parser);
 		PgfLiteral lit = 
 			gu_new_variant_i(parser->expr_pool,