[PATCH 0/2] parse-options: introduce die_for_required_opt() helper

Many built-in commands in Git manually check for option prerequisites (i.e., option X relies on option Y being present) using explicit conditional blocks and duplicated error message strings.

This short series comes out of a discussion with Christian about localization and code duplication. To address these issues, it introduces a centralized API helper that handles simple option prerequisites safely.

- Patch 1 introduces the `die_for_required_opt()` helper function 
  inside parse-options.
  
- Patch 2 cleans up `builtin/add.c` as a proof-of-concept by migrating 
  its manual prerequisite checks for '--ignore-missing' and 
  '--pathspec-file-nul' over to the new helper.

If this initial approach looks good, we can later extend the helper to handle more complex multi-option dependencies.

Siddharth Shrimali (2):
  parse-options: introduce die_for_required_opt()
  builtin/add: use die_for_required_opt() helper

 builtin/add.c   | 7 +++----
 parse-options.c | 7 +++++++
 parse-options.h | 3 +++
 3 files changed, 13 insertions(+), 4 deletions(-)