$ sudo apt-get update
$ sudo apt-get install ocamlmakefile 

ocamlmakefile is installed in your system.

Make ensure the ocamlmakefile package were installed using the commands given below,

$ sudo dpkg-query -l | grep ocamlmakefile *

You will get with ocamlmakefile package name, version, architecture and description in a table

ocamlmakefile package basic information: