multiple-inclusion.
(i386_register_u_addr): Remove prototype.
(register_u_addr): New prototype.
(REGISTER_U_ADDR): Redefine accordingly.
* i386v-nat.c: Improve several comments.
(i386_register_u_addr): Change signature and rename to
register_u_addr. Use FP_REGNUM_P. Rewrite slightly to get rid of
ubase variable.
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.