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_windows.cc b/winsup/cygwin/fhandler_windows.cc
index c9ef66c..3a2119f 100644
--- a/winsup/cygwin/fhandler_windows.cc
+++ b/winsup/cygwin/fhandler_windows.cc
@@ -112,7 +112,7 @@ fhandler_windows::read (void *buf, size_t& len)
 	      pthread::static_cancel_self ();
 	      break;
 	    }
-	  /*FALLTHRU*/
+	  fallthrough;
 	case WAIT_OBJECT_0 + 2:
 	  if (!PeekMessageW (ptr, hWnd_, 0, 0, PM_REMOVE))
 	    {