gitk: Show staged submodules regardless of ignore config

Currently setting submodule.<name>.ignore and/or diff.ignoreSubmodules to
"all" suppresses all output of submodule changes for gitk. This is really
confusing, as even when the user chooses to record a new commit for an
ignored submodule by adding it manually this change won't show up under
"Local changes checked in to index but not committed".

Fix that by using the '--ignore-submodules=dirty' option for both callers
of "git diff-index --cached" when the underlying git version supports that
option.

Signed-off-by: Jens Lehmann <Jens.Lehmann@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

gitk

@@ -5206,11 +5206,15 @@ proc dohidelocalchanges {} {
 # spawn off a process to do git diff-index --cached HEAD
 proc dodiffindex {} {
     global lserial showlocalchanges vfilelimit curview
-    global hasworktree
+    global hasworktree git_version
 
     if {!$showlocalchanges || !$hasworktree} return
     incr lserial
-    set cmd "|git diff-index --cached HEAD"
+    if {[package vcompare $git_version "1.7.2"] >= 0} {
+	set cmd "|git diff-index --cached --ignore-submodules=dirty HEAD"
+    } else {
+	set cmd "|git diff-index --cached HEAD"
+    }
     if {$vfilelimit($curview) ne {}} {
 	set cmd [concat $cmd -- $vfilelimit($curview)]
     }
@@ -7710,7 +7714,7 @@ proc addtocflist {ids} {
 }
 
 proc diffcmd {ids flags} {
-    global log_showroot nullid nullid2
+    global log_showroot nullid nullid2 git_version
 
     set i [lsearch -exact $ids $nullid]
     set j [lsearch -exact $ids $nullid2]
@@ -7731,6 +7735,9 @@ proc diffcmd {ids flags} {
 	    }
 	}
     } elseif {$j >= 0} {
+	if {[package vcompare $git_version "1.7.2"] >= 0} {
+	    set flags "$flags --ignore-submodules=dirty"
+	}
 	set cmd [concat | git diff-index --cached $flags]
 	if {[llength $ids] > 1} {
 	    # comparing index with specific revision