title: ocamlbuild: build plugin with options
body: <p>I'm trying to write an ocamlbuild plugin (myocamlbuild.ml) that will use definitions from another file. I have a lot of definitions that I'd like to be used across several build plugins and I wanted put them in their own file. I tried running ocamlbuild twice, once with -no-plugin just to build the plugin, e.g.</p>
  
  <p><code>
  ocamlbuild -no-plugin myocamlbuild.cmo
  </code></p>
  
  <p>and then again afterwards</p>
  
  <p><code>
  ocamlbuild actual-targets.otarget
  </code></p>
  
  <p>but when I run the second one it tries to rebuild the plugin and complains that it can't find the included library (even though it exists in the _build directory). So, is there any way that I can convince ocamlbuild to include '-I _build _build/coq_paths.cmx' on the command line? From 'ocamlbuild -help' it looks like there is a '-plugin-option' flag, but I can't find any way to use it.</p>
  
  <p>Thanks.</p>