* config/i386/i386mach.c: Explain this is for the old (probably
non-functional and/or obsolete) Mach stuff.
* m3-nat.c, config/nm-m3.h,
i386m3-nat.c, mipsm3-nat.c, ns32km3-nat.c,
config/i386/{i386m3.mh,i386m3.mt,tm-i386m3.h,xm-i386m3.h},
config/i386/{i386mk.mh,i386mk.mt,tm-i386mk.h,xm-i386mk.h},
config/mips/{mipsm3.mh,mipsm3.mt,tm-mipsm3.h,xm-mipsm3.h},
config/ns32k/{ns32km3.mh,ns32km3.mt,tm-ns32km3.h,xm-ns32km3.h}:
New files.
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.