Merge branch 'jk/snprintf-truncation'

Avoid unchecked snprintf() to make future code auditing easier. * jk/snprintf-truncation: fmt_with_err: add a comment that truncation is OK shorten_unambiguous_ref: use xsnprintf fsmonitor: use internal argv_array of struct child_process log_write_email_headers: use strbufs http: use strbufs instead of fixed buffers