Release version 1.2.1

Merge pull request google#175 from Quuxplusone/suggest-override

Fix -Wsuggest-override warnings from Clang

Tag open source release 1.1.10.

PiperOrigin-RevId: 515161676

Tag open source release 1.1.9.

PiperOrigin-RevId: 372007801

Tag open source release 1.1.8.

PiperOrigin-RevId: 289675084

Tag open source release 1.1.7.

zippy: Re-release snappy 1.1.5 as 1.1.6.

The migration from autotools to CMake in 1.1.5 wasn't as smooth as
intended. The SONAME / SOVERSION were broken in both build systems,
causing breakages in systems that upgraded from snappy 1.1.4 to 1.1.5,
as reported in Homebrew/homebrew-core#15274
and google#45.

Tag open source release 1.1.5.

1.1.4 release.

Release Snappy 1.1.3; getting the new Uncompress variant in a release…

… is nice,

and it's also good to finally get an official release out after the migration
to GitHub.

The GitHub releases are basically done by tagging a commit and then uploading
the .tar.gz file generated by make dist as a binary asset; GitHub will add
all files on the tagged commit on top of the tarball and recompress, but since
we don't have any nodist_* files in configure.ac, this works fine for us.
(As far as I can see, this behavior of GitHub--uncompressing the .tar.gz,
and the behavior of silently ignoring files in it that are also in the git
repository--is undocumented, but also seems to be used in some official
screenshots, so I guess we can rely on it.)

A=sesse
R=jeff