* ah/commit-id-to-clipboard:
gitk: offer "Copy commit ID to X11 selection" only on X11
gitk: support auto-copy comit ID to primary clipboard
gitk: prefs dialog: refine Auto-select UI
gitk: UI text: change "SHA1 ID" to "Commit ID"
Signed-off-by: Johannes Sixt <j6t@kdbg.org>