LLVM: Rely on a system installed LLVM
LLVM: Remove the optional dependency to conf-llvm-debug and add the external dependency on llvm-3.4-dev
Update patch to support natdynlink
llvm: Replace the external dependency for ubuntu
Merge pull request #1947 from andrewray/armv6-freebsd

Update patch to support natdynlink
Trigger travis
Merge pull request #1942 from jpdeplaix/master

LLVM: Rely on a system installed LLVM
Merge branch 'master' of github.com:ocaml/opam-repository