By Stephane Mahe and Layli Foroudi HOSTENS, France (Reuters) -Wildfires tore through the Gironde region of southwestern France on Wednesday, destroying homes and forcing the evacuation of more than 8,000 residents, some of whom had clambered onto rooftops as the flames got closer. Skies darkened from the smoke billowing from forests destroyed by fires that have razed more than 6,000 hectares (14,826 acres) and were continuing to burn out of control despite the efforts of firefighters backed by water-bombing aircraft. France, like the rest of Europe, has been struggling this summer with success…