Merge branch 'rj/no-sign-compare' into maint

Many codepaths have been updated to squelch -Wsign-compare
warnings.

* rj/no-sign-compare:
  ALLOC_GROW: avoid -Wsign-compare warnings
  cache.h: hex2chr() - avoid -Wsign-compare warnings
  commit-slab.h: avoid -Wsign-compare warnings
  git-compat-util.h: xsize_t() - avoid -Wsign-compare warnings

diff --cc builtin/pack-objects.c
Simple merge

diff --cc config.c
Simple merge

diff --cc diff.c
Simple merge