Merge branch 'da/xdiff-w-sign-compare-workaround'

Noises from "-Wsign-compare" in the borrowed xdiff code has been squelched. * da/xdiff-w-sign-compare-workaround: xdiff: avoid signed vs. unsigned comparisons in xutils.c xdiff: avoid signed vs. unsigned comparisons in xpatience.c xdiff: avoid signed vs. unsigned comparisons in xhistogram.c xdiff: avoid signed vs. unsigned comparisons in xemit.c xdiff: avoid signed vs. unsigned comparisons in xdiffi.c xdiff: move sign comparison warning guard into each file