gitk: Make the background color of marked lines configurable

This makes it possible for the user to configure the background color
of lines that are "marked".  At the moment only the "show the origin
of this line" function marks lines.  This also makes the user's choice
persistent by saving it in ~/.gitk.

Signed-off-by: Paul Mackerras <paulus@samba.org>

gitk

@@ -2415,7 +2415,7 @@ proc savestuff {w} {
     global viewname viewfiles viewargs viewargscmd viewperm nextviewnum
     global cmitmode wrapcomment datetimeformat limitdiffs
     global colors bgcolor fgcolor diffcolors diffcontext selectbgcolor
-    global autoselect extdifftool perfile_attrs
+    global autoselect extdifftool perfile_attrs markbgcolor
 
     if {$stuffsaved} return
     if {![winfo viewable .]} return
@@ -2439,6 +2439,7 @@ proc savestuff {w} {
 	puts $f [list set fgcolor $fgcolor]
 	puts $f [list set colors $colors]
 	puts $f [list set diffcolors $diffcolors]
+	puts $f [list set markbgcolor $markbgcolor]
 	puts $f [list set diffcontext $diffcontext]
 	puts $f [list set selectbgcolor $selectbgcolor]
 	puts $f [list set extdifftool $extdifftool]
@@ -6658,11 +6659,11 @@ proc getblobline {bf id} {
 }
 
 proc mark_ctext_line {lnum} {
-    global ctext
+    global ctext markbgcolor
 
     $ctext tag delete omark
     $ctext tag add omark $lnum.0 "$lnum.0 + 1 line"
-    $ctext tag conf omark -background "#e0e0ff"
+    $ctext tag conf omark -background $markbgcolor
     $ctext see $lnum.0
 }
 
@@ -9731,7 +9732,7 @@ proc chg_fontparam {v sub op} {
 proc doprefs {} {
     global maxwidth maxgraphpct
     global oldprefs prefstop showneartags showlocalchanges
-    global bgcolor fgcolor ctext diffcolors selectbgcolor
+    global bgcolor fgcolor ctext diffcolors selectbgcolor markbgcolor
     global tabstop limitdiffs autoselect extdifftool perfile_attrs
 
     set top .gitkprefs
@@ -9824,6 +9825,12 @@ proc doprefs {} {
 		      "diff hunk header" \
 		      [list $ctext tag conf hunksep -foreground]]
     grid x $top.hunksepbut $top.hunksep -sticky w
+    label $top.markbgsep -padx 40 -relief sunk -background $markbgcolor
+    button $top.markbgbut -text [mc "Marked line bg"] -font optionfont \
+	-command [list choosecolor markbgcolor {} $top.markbgsep \
+		      [mc "marked line background"] \
+		      [list $ctext tag conf omark -background]]
+    grid x $top.markbgbut $top.markbgsep -sticky w
     label $top.selbgsep -padx 40 -relief sunk -background $selectbgcolor
     button $top.selbgbut -text [mc "Select bg"] -font optionfont \
 	-command [list choosecolor selectbgcolor {} $top.selbgsep background setselbg]
@@ -10369,6 +10376,7 @@ set diffcolors {red "#00a000" blue}
 set diffcontext 3
 set ignorespace 0
 set selectbgcolor gray85
+set markbgcolor "#e0e0ff"
 
 set circlecolors {white blue gray blue blue}