Fix build with OCaml 3.12

Summary: The build fails with ocaml 3.12 because we pass arguments to gcc in the -l <library> style, and ocaml 3.12 puts all the file arguments first and all the -something ones last, so it mangles the command line.

This fixes that issue by changing those to single-argument versions: -l<library>, -I<dir>, -L<library path>.

Github issue #4184

Reviewed By: @pathsny

Differential Revision: D1669106

Signature: t1:1669106:1415643437:1a452f8f8e584f5c63cdf08156bebad6f95fcedd