Merge branch 'vendor/DIFFUTILS'

diff --cc contrib/diffutils/lib/wcwidth.c
Simple merge

diff --cc contrib/diffutils/src/diff.c
Simple merge

diff --cc contrib/diffutils/src/diff3.c
Simple merge

diff --cc contrib/diffutils/src/sdiff.c
Simple merge

diff --cc contrib/diffutils/src/side.c
Simple merge