DMD exit code -9

[Craig Dillabaugh]

I am trying to build a small application (I am using DUB) and 
when I try to build, I get the following output:

> dub build
dub: /usr/lib64/libcurl.so.4: no version information available 
(required by dub)
vibe-d: ["vibe-d", "libevent", "openssl"]
vibe-d: ["vibe-d", "libevent", "openssl"]
libd: ["libd", "vibe-d", "libevent", "openssl"]
classify: ["classify", "vibe-d", "libevent", "openssl", "libd", 
"vibe-d", "libevent", "openssl"]
Building vibe-d configuration "libevent", build type debug.
Running dmd...
FAIL 
../../../../../.dub/packages/vibe-d-master/.dub/build/libevent-debug-linux.posix-x86_64-dmd-7A48A3727C6BBE022213B1765700F4A5 
vibe-d staticLibrary
Error executing command build: DMD compile run failed with exit 
code -9

Does anyone know what 'exit code -9' means, or where I could even 
go to find a listing of what the various exit codes for DMD mean. 
  I've searched around the WWW a bit and can't find any such list.