* gdbtk.tcl (gdb_prompt): Set this early on.

	* gdbtk.tcl (gdb_prompt): Set this early on.
	(create_command_window): Use gdb_prompt rather than "(gdb) ".
	(gdbtk_tcl_preloop): Proc executed just prior to Tk main loop.
	(tclsh): If an evaluation window already exists, just bring it
	to the front instead of trying to create another.
	* gdbtk.c (tk_command_loop): New function.
	(gdbtk_init): Call tk_command_loop rather than Tk_MainLoop.