get linked to nm.h, xm.h, and tm.h respectively by configure,
moved to appropriate config/<cpu> subdirectory.
* nm-sysv4.h, xm-sysv4.h, tm-sysv4.h, tm-sunos.h, nm-trash.h:
Native, host, and target files that are common across more than
one cpu architecture and included by one of the configured
native, host, or target files, get moved to config directory.
* config/sun3os3.mh, config/sun3os4.mh (NAT_FILE, NATDEPFILES):
new macros for native support.
(XDEPFILES): moved infptrace.o and inftarg.o to NATDEPFILES,
removed sun3-xdep.o.
* xm-sun3.h (ATTACH_DETACH, FETCH_INFERIOR_REGISTERS): moved to
nm-sun3.h.
* sun3-xdep.c: removed. All code is now in sun3-nat.c.
* sun3-nat.c, nm-sun3.h: new files for native support.
