gdb/

	Conditional tracepoints.
	* ax-gdb.h (gen_eval_for_expr): Declare.
	* ax-gdb.c (gen_expr): Generate bytecodes for BINOP_EQUAL
	and other comparisons.
	(gen_eval_for_expr): New function.
	(agent_eval_command): New maintenance command.
	(_initialize_ax_gdb): Define the command.
	* remote.c (struct remote_state): New field cond_tracepoints.
	(PACKET_ConditionalTracepoints): New packet config type.
	(remote_cond_tracepoint_feature): New function.
	(remote_protocol_features): Add ConditionalTracepoints.
	(remote_supports_cond_tracepoints): New function.
	(_initialize_remote): Add ConditionalTracepoints.
	* tracepoint.c (download_tracepoint): Add conditional.
	* NEWS: Mention conditional tracepoints.

	gdb/doc/
	* gdb.texinfo (Tracepoint Conditions): New section.
	(General Query Packets): Describe ConditionalTracepoints.
	(Tracepoint Packets): Describe condition field.
	(Maintenance Commands): Describe maint agent-eval.
	* agentexpr.texi (Using Agent Expressions): Mention eval usage.

	gdb/testsuite/
	* gdb.trace/tracecmd.exp: Add basic test of tracepoint conditions.