Config.h header missing from buildbot?

Folks,

My buildbot often loses its config.h file:

Driver.cpp:42:33: fatal error: clang/Config/config.h: No such file or directory
#include “clang/Config/config.h”
^
compilation terminated.

http://lab.llvm.org:8011/builders/clang-native-arm-cortex-a15/builds/480/steps/compile/logs/stdio

I’m not cleaning before making, but I’d assume files wouldn’t simply disappear like that.

I have restarted the bot quite a few times already (by removing the whole build directory), to no avail.

Ideas?

cheers,
–renato