Add fall-through comments.

This patch adds fall-through comments in some cases where -Wextra
produces implicit-fallthrough warnings.

The patch is non-exhaustive.  Apart from architecture-specific code
for non-x86_64 architectures, it does not change sunrpc/xdr.c (legacy
code, probably should have such changes, but left to be dealt with
separately), or places that already had comments about the
fall-through but not matching the form expected by
-Wimplicit-fallthrough=3 (the default level with -Wextra; my
inclination is to adjust those comments to match rather than
downgrading to -Wimplicit-fallthrough=1 to allow any comment), or one
place where I thought the implicit fallthrough was not correct and so
should be handled separately as a bug fix.  I think the key thing to
consider in review of this patch is whether the fall-through is indeed
intended and correct in each place where such a comment is added.

Tested for x86_64.

	* elf/dl-exception.c (_dl_exception_create_format): Add
	fall-through comments.
	* elf/ldconfig.c (parse_conf_include): Likewise.
	* elf/rtld.c (print_statistics): Likewise.
	* locale/programs/charmap.c (parse_charmap): Likewise.
	* misc/mntent_r.c (__getmntent_r): Likewise.
	* posix/wordexp.c (parse_arith): Likewise.
	(parse_backtick): Likewise.
	* resolv/ns_ttl.c (ns_parse_ttl): Likewise.
	* sysdeps/x86/cpu-features.c (init_cpu_features): Likewise.
	* sysdeps/x86_64/dl-machine.h (elf_machine_rela): Likewise.

1 files changed, 2 insertions, 0 deletions

diff --git a/misc/mntent_r.c b/misc/mntent_r.c
index 1d5e259..5d88c45 100644
--- a/misc/mntent_r.c
+++ b/misc/mntent_r.c
@@ -174,8 +174,10 @@ __getmntent_r (FILE *stream, struct mntent *mp, char *buffer, int bufsiz)
     {
     case 0:
       mp->mnt_freq = 0;
+      /* Fall through.  */
     case 1:
       mp->mnt_passno = 0;
+      /* Fall through.  */
     case 2:
       break;
     }