* config/m88k/m88k.mh: Use xm-dgux.h.
* config/m88k/xm-m88k.h: New file, with HOST_BYTE_ORDER,
MAKEVA_END and MAKEVA_ARG.
* config/m88k/xm-*.h: Include m88k/xm-m88k.h.
* printcmd.c: Remove __INT_VARARGS_H code; now in xm-m88k.h.
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.