SQL & PL/SQL

I am trying to pass index hints dynamically to sql queries using dbms_sql.

Select :hint emp_name from EMPLOYEE emp; -> This is working fine

Below cases are failing while parsing (dbms_sql.parse)
ex:

 Select :hint count(1) from EMPLOYEE emp;
    Select :hint Distinct emp_name from EMPLOYEE emp;
    Select :hint emp.emp_name from EMPLOYEE emp;

Getting error: ORA-00923: FROM keyword not found where expected
How to handle index hints in the above failed cases?
Oracle version: Oracle Database 12c Enterprise Edition Release 12.1.0.2.0
Here example hint:
l_sql_hint := /*+ full(emp) */
Code:

    curs_handle := dbms_sql.open_cursor;

    dbms_sql.parse(curs_handle, l_sql, dbms_sql.native);

    IF l_sql_hint IS NOT NULL THEN
        dbms_sql.bind_variable(curs_handle, ':hint', l_sql_hint);
    END IF;

    no_of_rows_affected := dbms_sql.EXECUTE(curs_handle);