solver: extract_diff: deal with missing "diff --git" line

Rewrite the patch extraction loop using a single regexp which
accounts for missing "diff --git ..." lines and is capable of
extracting pathnames off the "+++ b/foo" line.

This fixes the solving of blob "96f1c7f" off
<2841d2de-32ad-eae8-6039-9251a40bb00e@tngtech.com>
in git@vger archives.

v2:

* Fix regressions in git@vger archives:
  - git/776fa90f7f/s/?b=contrib/git-jump/git-jump
    (fallback to "old mode" properly)
  - git/5cd8845/s/?b=submodule.c
    (no leading space in context)

* use "state" in a Perl <5.28.0-compatible way

0 files changed, 0 insertions, 0 deletions