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.
* tm-i386bsd.h, xm-i386bsd.h: New config files.
* i386b-nat.c: New native support file.
* configure.in: Add host and target for i[34]86-*-bsd*.
* config/i386bsd.mh, config/i386bsd.mt: New config files.