Trump the builder carves his legacy in stone as pressures mount

WASHINGTON, Aug 19 (Reuters) - With Iran diplomacy stalled, financial markets uneasy and his approval rating at another low point, President Donald Trump reverted to familiar territory on Wednesday, leading reporters on a tour of White House construction projects he hopes will cement his legacy. The former real estate developer spent about 30 minutes guiding reporters across the South Lawn, touting a new granite helipad, a $400 million ballroom and other renovations he said would modernize the…