Add more 'fall through' switch comments
Commit
a455452d (LINUX 5.3: Add comments for fallthrough switch cases)
added the special /* fall through */ comment to various switch/case
blocks, in order to avoid implicit-fallthrough warnings from causing
the build to fail when building the Linux kernel module.
In this commit, add additional /* fall through */ comments to the rest
of the tree where falling through is intentional. Add a "break;" in one
place in dumptool.c where falling through seems like a mistake, and flag
certain functions as AFS_NORETURN to avoid needing to explicitly break
or fallthrough.
Check for the availability of the -Wimplicit-fallthrough compiler flag
and use it when --enable-checking is set, to prevent additional cases
from creeping into the tree.
Note: the -Wimplicit-fallthrough compiler flag was added in gcc 7.
Change-Id: Iae34e7969606603da8358d7cfa5fd04279b218dc
Reviewed-on: https://gerrit.openafs.org/14125
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
Tested-by: BuildBot <buildbot@rampaginggeek.com>