* configure.host (alpha*-*-osf[12]*): Remove support.

	* configure.host (alpha*-*-osf[12]*): Remove support.
	* NEWS: Mention removed configurations.

	* config/alpha/alpha-osf1.mh: Delete file.
	* config/alpha/alpha-osf2.mh: Delete file.
	* config/alpha/alpha-osf3.mh (NATDEPFILES): Remove inftarg.o
	and infptrace.o.
	* config/alpha/nm-osf.h: Delete file.
	* config/alpha/nm-osf2.h: Delete file.
	* config/alpha/nm-osf3.h: Do not include "nm-osf2.h".
	(START_INFERIOR_TRAPS_EXPECTED): Copy from nm-osf.h.
	(PROCFS_DONT_TRACE_FAULTS): Copy from nm-osf2.h.

	* alpha-nat.c (ALPHA_UNIQUE_PTRACE_ADDR): Do not define.
	(register_addr, kernel_u_size): Remove.
	Do not check for "defined(USE_PROC_FS) || defined(HAVE_GREGSET_T)".