I tried install VibeNews on another computer:

$cd vibenews
$dub run
FAIL ../../home/donald/.dub/packages/vibe-d-0.7.21-alpha.1/.dub/build/libevent-debug-linux.posix-x86_64-dmd-AB0707232CA963B5DA23C2232BBED51B vibe-d staticLibrary
Error executing command run: DMD compile run failed with exit code -9
$dub upgrade
Removing present package of libevent ~master
Error executing command upgrade: Untracked file found, aborting package removal: /home/donald/.dub/packages/libevent-master/C/event2

$ dub list
Packages present in the system and known to dub:
  vibenews ~master: /opt/vibenews
  libev ~master: /home/donald/.dub/packages/libev-master
  libevent ~master: /home/donald/.dub/packages/libevent-master
  vibe-d 0.7.21-alpha.1: /home/donald/.dub/packages/vibe-d-0.7.21-alpha.1
  userman 0.0.12: /home/donald/.dub/packages/userman-0.0.12
  openssl ~master: /home/donald/.dub/packages/openssl-master
  antispam 0.0.5: /home/donald/.dub/packages/antispam-0.0.5

How do I fix this?