(alphafbsd_init_abi): Set solib_svr4_fetch_link_map_offsets to
svr4_lp64_fetch_link_map_offsets.
* Makefile.in (alphafbsd-tdep.o): Update dependencies.
* config/alpha/fbsd.mt (TDEPFILES): Add corelow.o, solib.o and
solib-svr4.o.
* config/alpha/fbsd.mh (NATDEPFILES): Remove solib.o, solib-svr4.o
and solib-legacy.o.
* config/alpha/nm-fbsd.h: Don't include "solib.h".