[patch] Fix handling of Trace Buttons

[Fernando Nasser <fnasser at redhat dot com>]

While rewriting the toolbar code I found a bug in the old code.
This patch fixes it.

The error here is a classic itcl inheritance one.
Variables are not "virtual", so overloading them won't work at all.
As a result, the variable "Browsing" was never set to anything
different than 0 in the base class.

I renamed it to ToolBrowsing and made the derived class set it properly.
I also got rid of a pair of unused variables.

The trace buttons are now working properly.
Index: srcbar.tcl
===================================================================
RCS file: /cvs/cvsfiles/devo/gdb/gdbtk/library/srcbar.tcl,v
retrieving revision 1.1.20.1
diff -c -p -r1.1.20.1 srcbar.tcl
*** srcbar.tcl	2000/12/13 20:50:13	1.1.20.1
--- srcbar.tcl	2000/12/28 22:45:22
*************** class GDBSrcBar {
*** 446,451 ****
--- 446,452 ----
      debug "set_control_mode called with mode $mode"
      if {$mode} {
        set Browsing 1
+       set ToolBrowsing 1
        $Buttons(view) configure -image run_expt_img -command "$this set_control_mode 0"
        balloon register $Buttons(view) "Switch to Control mode"
        # Now swap out the buttons...
*************** class GDBSrcBar {
*** 456,461 ****
--- 457,463 ----
  	tfind_cmd {tfind none}
        }
        set Browsing 0
+       set ToolBrowsing 0
        $Buttons(view) configure -image watch_movie_img -command "$this set_control_mode 1"
        balloon register $Buttons(view) "Switch to Browse mode"
        # Now swap out the buttons...
Index: toolbar.tcl
===================================================================
RCS file: /cvs/cvsfiles/devo/gdb/gdbtk/library/toolbar.tcl,v
retrieving revision 1.1.88.1
diff -c -p -r1.1.88.1 toolbar.tcl
*** toolbar.tcl	2000/12/13 23:02:15	1.1.88.1
--- toolbar.tcl	2000/12/28 22:45:22
*************** class GDBToolBar {
*** 410,416 ****
    # ------------------------------------------------------------------
    public method enable_ui {on} {
      global tcl_platform
!     debug "Toolbar::enable_ui $on - Browsing=$Browsing"
  
      # Do the enabling so that all the disabling happens first, this way if a
      # button belongs to two groups, enabling takes precedence, which is probably right.
--- 410,416 ----
    # ------------------------------------------------------------------
    public method enable_ui {on} {
      global tcl_platform
!     debug "Toolbar::enable_ui $on - ToolBrowsing=$ToolBrowsing"
  
      # Do the enabling so that all the disabling happens first, this way if a
      # button belongs to two groups, enabling takes precedence, which is probably right.
*************** class GDBToolBar {
*** 424,430 ****
  			   Detach disabled}
        }
        1 {
! 	if {!$Browsing} {
  	  set enable_list {Trace disabled \
  			     Control normal \
  			     Other normal \
--- 424,430 ----
  			   Detach disabled}
        }
        1 {
! 	if {!$ToolBrowsing} {
  	  set enable_list {Trace disabled \
  			     Control normal \
  			     Other normal \
*************** class GDBToolBar {
*** 795,803 ****
    # This is a handle on our parent source window.
    protected variable source {}
  
!   public variable Tracing 0     ;# Is tracing enabled for this gdb?
!   public variable Browsing   0  ;# Are we currently browsing a trace experiment?
!   public variable Collecting 0  ;# Are we currently collecting a trace experiment?
  
    # The list of all control buttons (ones which should be disabled when
    # not running anything or when inferior is running)
--- 795,801 ----
    # This is a handle on our parent source window.
    protected variable source {}
  
!   public variable ToolBrowsing   0  ;# Are we currently browsing a trace experiment?
  
    # The list of all control buttons (ones which should be disabled when
    # not running anything or when inferior is running)