[PATCH 0/3] Add a function skip_prefix_if_present()

These patches apply on top of gitster/nd/more-skip-prefix.

I noticed that Duy's new function skip_prefix_defval() was mostly being called with its first and third arguments the same. So introduce a function skip_prefix_if_present() that implements this pattern.

Michael Haggerty (3):
  Add and use a function skip_prefix_if_present()
  diff_scoreopt_parse(): use skip_prefix_if_present()
  rev_is_head(): use skip_prefix()

 builtin/checkout.c    |  4 ++--
 builtin/fast-export.c |  2 +-
 builtin/merge.c       |  2 +-
 builtin/show-branch.c | 15 ++++++++-------
 diff.c                |  6 +++---
 git-compat-util.h     |  5 +++++
 git.c                 |  2 +-
 notes.c               |  4 ++--
 refs.c                |  2 +-
 wt-status.c           |  4 ++--
 10 files changed, 26 insertions(+), 20 deletions(-)