Mexico's Cemex, one of the world's largest cement producers, is open to providing the raw materials for U.S. President Donald Trump's promised wall between the two neighbors, daily newspaper Reforma reported on Wednesday. "We will gladly do it," Cemex President Rogelio Zambrano told the newspaper, when asked if the company would provide a cement estimate for the controversial project, potentially worth billions of dollars. It was not known which other companies might participate or the likely demand for cement for the wall, Zambrano said. On Wednesday a spokesperson for Cemex provided a statement to Telemundo. "Cemex is not a U.S....