* configure.in (AC_CHECK_HEADERS): Check for sys/procfs.h.

	* configure.in (AC_CHECK_HEADERS): Check for sys/procfs.h.
	Also check for gregset_t and fpregset_t types.
	* configure: Regenerate.
	* core-regset.c (sys/procfs.h): Only include if HAVE_SYS_PROCFS_H
 	is defined.
	(fetch_core_registers): Turn into stub unless both HAVE_GREGSET_T
 	and HAVE_FPREGSET_T are defined.  These changes allow systems
 	like linux that are migrating to /proc support to use a single
 	configuration for both new and old versions.

	* config/i386/linux.mt: Note that this is now for both a.out and
	ELF systems.
	* config/i386/linux.mh (NATDEPFILES): Add solib.o, core-regset.o,
	i386v4-nat.o
	* config/i386/tm-linux.h (tm-sysv4.h): Include.
	* config/i386/xm-linux.h (solib.h): Include
	(SVR4_SHARED_LIBS): Define.
	* i386v4-nat.c: Only compile if HAVE_SYS_PROCFS_H is defined.
	(supply_gregset, fill_gregset): Compile if HAVE_GREGSET_T defined.
	(supply_fpregset, fill_fpregset): Compile if HAVE_FPREGSET_T defined.