Merge tag 0.28.4

No functionality changes merged, since the bug in question was already
fixed on master.

diff --cc NEWS
index 0a4ab4bbe12e952eebfec6eb35840a8466301f11,c5b7eec97f98d5e5341f664d30d4eb1c988f6fac..26b8160c8ee253821604c0063f0eb8ed6539f1dd
--- 1/NEWS
--- 2/NEWS
+++ b/NEWS
@@@ -1,18 -1,12 +1,27 @@@
 +Notmuch 0.29 (UNRELEASED)
 +=========================
 +
 +Command Line Interface
 +----------------------
 +
 +`notmuch show` now supports --body=false and --include-html with
 +--format=text
 +
 +Emacs
 +-----
 +
 +Support for GNU Emacs older than 25.1 is deprecated with this release,
 +and may be removed in a future release.
 +
+ Notmuch 0.28.4 (2019-05-05)
+ ===========================
+ 
+ Command line interface
+ ----------------------
+ 
+ Fix a spurious error when using `notmuch show --raw` on messages whose
+ size is a multiple of the internal buffer size.
+ 
  Notmuch 0.28.3 (2019-03-05)
  ===========================