[PATCH v2 0/2] Introduce config variable "diff.primer"

The next two patches introduce a means by which to specify non-default options porcelain diff automatically obeys. This version v2 fixes the problem with v1 (violation of plumbing guarantee) by switching to opt_in rather than opt_out semantics. v2 also corrects code style to mimic established convention.

At least one list poster expressed interest in implementing complimentary functionality, i.e. "primer.*": http://article.gmane.org/gmane.comp.version-control.git/107158 "primer.diff" compliments "diff.primer", the two styles in no way exclude each other, and therefore "primer.*" is a good opportunity for future work.

Keith Cascio (2):
 Introduce config variable "diff.primer"
 Test functionality of new config variable "diff.primer"

 Documentation/config.txt       |   14 ++++
 Documentation/diff-options.txt |   10 +++
 builtin-diff.c                 |    2 +
 diff.c                         |   77 +++++++++++++++++++++---
 diff.h                         |   14 ++++-
 gitk-git/gitk                  |   16 +++---
 t/t4035-diff-primer.sh         |  129 ++++++++++++++++++++++++++++++++++++++++
 7 files changed, 242 insertions(+), 20 deletions(-)