Cygwin: Add 'fallthrough' pseudo keyword for switch/case use

This patch has been inspired by the Linux kernel patch

  294f69e662d1 compiler_attributes.h: Add 'fallthrough' pseudo keyword for switch/case use

written by Joe Perches <joe AT perches DOT com> based on an idea from
Dan Carpenter <dan DOT carpenter AT oracle DOT com>.  The following text
is from the original log message:

Reserve the pseudo keyword 'fallthrough' for the ability to convert the
various case block /* fallthrough */ style comments to appear to be an
actual reserved word with the same gcc case block missing fallthrough
warning capability.

All switch/case blocks now should end in one of:

	break;
	fallthrough;
	goto <label>;
	return [expression];
	continue;

In C mode, GCC supports the __fallthrough__ attribute since 7.1,
the same time the warning and the comment parsing were introduced.

Cygwin-only: add an explicit -Wimplicit-fallthrough=5 to the build
flags.

1 files changed, 1 insertions, 1 deletions

diff --git a/winsup/cygwin/fhandler_dsp.cc b/winsup/cygwin/fhandler_dsp.cc
index b5c685bf8..e105514cb 100644
--- a/winsup/cygwin/fhandler_dsp.cc
+++ b/winsup/cygwin/fhandler_dsp.cc
@@ -1067,7 +1067,7 @@ fhandler_dev_dsp::open (int flags, mode_t)
     case O_RDWR:
       if ((num_in = waveInGetNumDevs ()) == 0)
 	err = ENXIO;
-      /* Fall through */
+      fallthrough;
     case O_WRONLY:
       if ((num_out = waveOutGetNumDevs ()) == 0)
 	err = ENXIO;