* fork-child.c (fork_inferior), inferior.h: init_trace_fun now

	* fork-child.c (fork_inferior), inferior.h:  init_trace_fun now
	returns a possibly modified pid.
	* inftarg.c (ptrace_him):  Now returns pid;
	* m3-nat.c (m3_trace_him):  Now returns pid;
	* infcmd.c (run_command):  Minor cleanup.
	* infrun.c (wait_for_inferior):  Add another check for one_stepped
	near where we read the pc to avoid erroneously setting
	random_signal for multi-threaded support.
	* procfs.c:  Add support for Solaris LWPs.  Remove def of
	LOSING_POLL.  Many cleanups...  Several workarounds for Solaris
	lossage.  System call entry and exit are now handled by
	dynamically registered handlers.
	* (syscallname):  Don't barf when handed an unknown syscall
	number.
	* (info_proc_syscalls):  Ditto.
	* sol-thread.c:  New file.  Implements Solaris thread support.
	* symfile.c (symbol_file_add):  Add call to target_new_objfile to
	notify target-dependent code about new symbol tables.
	* (clear_symtab_users):  Call target_new_objfile to notify it of
	the removal of all symbol tables.
	* target.c (push_target):  Make sure that to_close is non-zero
	before calling it.
	* target.h (target_new_objfile):  Provide default.
	* config/alpha/nm-osf2.h:  Define LOSING_POLL because this version
	of OSF can't hack using poll with /proc.
	* config/sparc/nm-sun4sol2.h (target_new_objfile):  Define to be
	sol-thread-new-objfile.
	* config/sparc/sun4sol2.mh:  Add sol-thread.o to NATDEFFILES, and
	add libthread_db.so.1 to NAT_CLIBS.
	* config/sparc/tm-sun4sol2.h:  Define PIDGET, TIDGET, and
	target_pid_to_str.