These changes knock several seconds off startup time on my system.

2003-02-03  Martin M. Hunt  <hunt@redhat.com>

	* library/interface.tcl (gdbtk_locate_main): Rewrite for efficiency.
	No longer uses gdb_search.  Caches result. 
	(initialize_gdbtk): Initialize gdb_locate_main cache.
	* library/main.tcl: Call initialize_gdbtk after loading prefs.