Use __attribute__((fallthrough)) rather than magic GCC comments.

GCC added an implicit-fallthrough warning a while back, where it
would complain if you had a nontrivial "case:" block that didn't end
with break, return, or something like that.  Clang recently added
the same thing.

GCC, however, would let you annotate a fall-through as intended by
any of various magic "/* fall through */" comments.  Clang, however,
only seems to like "__attribute__((fallthrough))".  Fortunately, GCC
accepts that too.

A previous commit in this branch defined a FALLTHROUGH macro to do
the right thing if GNUC is defined; here we replace all of our "fall
through" comments with uses of that macro.

This is an automated commit, made with the following perl one-liner:

  #!/usr/bin/perl -i -p
  s#/\* *falls? ?thr.*?\*/#FALLTHROUGH;#i;

(In order to avoid conflicts, I'm applying this script separately to
each maint branch. This is the 0.4.2 version.)

1 files changed, 1 insertions, 1 deletions

diff --git a/src/feature/control/control_cmd.c b/src/feature/control/control_cmd.c
index de1bef7e59..68d05abb73 100644
--- a/src/feature/control/control_cmd.c
+++ b/src/feature/control/control_cmd.c
@@ -1887,7 +1887,7 @@ handle_control_add_onion(control_connection_t *conn,
   case RSAE_BADAUTH:
     control_write_endreply(conn, 512, "Invalid client authorization");
     break;
-  case RSAE_INTERNAL: /* FALLSTHROUGH */
+  case RSAE_INTERNAL: FALLTHROUGH;
   default:
     control_write_endreply(conn, 551, "Failed to add Onion Service");
   }