Merge branch 'ti/support-sha256'

* ti/support-sha256:
  gitk: Add support of SHA256 repositories

diff --cc gitk
index 0df4eee7333234c09d097c58f750ba2ea475278a,64a074ab02217f38cb4e4611fe1433e8b59c1ded..fa0d9a94e5fddf7dbdd7733d9d6a0a4d63c4cf47
--- 1/gitk
--- 2/gitk
+++ b/gitk
@@@ -9655,10 -9639,10 +9673,10 @@@ proc copyreference {} 
  
      set format "%h (\"%s\", %ad)"
      set cmd [list git show -s --pretty=format:$format --date=short]
-     if {$autosellen < 40} {
+     if {$autosellen < $hashlength} {
          lappend cmd --abbrev=$autosellen
      }
 -    set reference [eval exec $cmd $rowmenuid]
 +    set reference [safe_exec [concat $cmd $rowmenuid]]
  
      clipboard clear
      clipboard append $reference