By Andrew R.C. Marshall MANILA (Reuters) - Jason Madarang, awaiting trial on a charge of drug use, is in a muggy, windowless cell in a Manila prison so overcrowded that inmates must sleep in halls and stairwells and share each toilet with 150 other men. But with President Rodrigo Duterte's "war on drugs" raging beyond the walls of Quezon City Jail, Madarang says he is lucky.