Thousands of Muslims in Pakistan poured out of prayer services to join anti-France protests on Friday, as the French president’s vow to protect the right to caricature the Prophet Muhammad continues to roil the Muslim world. Crowds led by Islamic parties chanted anti-France slogans, raised banners and clogged major roads en route to a Sufi shrine. Dozens of people furiously stomped on French flags and cried for the boycott of French products.