Changes imported from Abseil "staging" branch:

  - d79c005bda08783cd496c41dbd51a5d7e520c9e2 Fix typo in ByLength example (comment). by Abseil Team <absl-team@google.com>
  - 0751d4f0e61f70e50f4771ca9843bd90895ec0bc Enable RAW_LOG on NaCl via POSIX write(), which it suppor... by Abseil Team <absl-team@google.com>
  - 4a63f87b9b1c9d738da21fc0ffa638876a12facf Remove use of assert() in .h and .inc files to reduce cha... by Alex Strelnikov <strel@google.com>

GitOrigin-RevId: d79c005bda08783cd496c41dbd51a5d7e520c9e2
Change-Id: I0c5d064faa1b8e6b703d388af2b8957cc906dd7f