ocaml-obuild from openSUSE:Backports:SLE-15-SP1 project

需要 standard ，用 root 執行：

zypper addrepo https://download.opensuse.org/repositories/openSUSE:Backports:SLE-15-SP1/standard/openSUSE:Backports:SLE-15-SP1.repo
zypper refresh
zypper install ocaml-obuild