Merge branch 'jm/maint-strncpy-diff-no-index'

The "diff --no-index" codepath used limited-length buffers, risking pathnames getting truncated. Update it to use the strbuf API. By Jim Meyering (1) and Junio C Hamano (1) * jm/maint-strncpy-diff-no-index: diff --no-index: use strbuf for temporary pathnames diff: avoid stack-buffer-read-overrun for very long name