FRAME_CHAIN, FRAMELESS_FUNCTION_INVOCATION, FRAME_SAVED_PC): Define to make backtracing through the various sigtramp handlers work.
config files moved to an appropriate config/<cpu> subdirectory. * nm-*, xm-*, tm-*: All native, host, and target files, which get linked to nm.h, xm.h, and tm.h respectively by configure, moved to appropriate config/<cpu> subdirectory.