Make /bin/clear work again.

After I made stdio buffered, we were dropping anything unflushed on exit.
Since /bin/clear just prints out some escape sequences without a newline,
the entire buffer was being discarded.

Also add VirtualConsole::clear() that handles clearing of background VC's.

1 files changed, 3 insertions, 0 deletions

diff --git a/LibC/entry.cpp b/LibC/entry.cpp
index d24be1ff07..2753137e2c 100644
--- a/LibC/entry.cpp
+++ b/LibC/entry.cpp
@@ -41,6 +41,9 @@ extern "C" int _start()
         goto epilogue;
     status = main(argc, argv);
 
+    fflush(stdout);
+    fflush(stderr);
+
 epilogue:
     Syscall::invoke(Syscall::SC_exit, status);