Define IN_SIGTRAMP and backtrace correctly through signal handlers.
* config/m88k/delta88.mh: Fix comment. * config/m88k/tm-delta88.h: Remove unused BCS define. * config/m88k/{tm-delta88v4.h,xm-delta88v4.h,nm-delta88v4.h}: New files. * configure.in: Recognize m88*-motorola-sysv4*. * m88k-nat.c: Always include sys/types.h; don't depend on USG.
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.