Make menus on Haiku work better

* src/haikuterm.c (haiku_read_socket): Don't send up events for
ungrabbed buttons.
2 jobs for master in 90 minutes and 39 seconds (queued for 10 seconds)
Status Job ID Name Coverage
  Build Images
passed #38760
build-image-inotify

01:26:18

 
  Normal
passed #38761
test-src-inotify

00:04:21