From: Kubo Takehiro <kubo@...>
Date: 2012-05-07T21:43:40+09:00
Subject: Re: [C exten] mkmf: how to include .c and .h files within a subdirectory?

On Mon, May 7, 2012 at 7:58 AM, Iņaki Baz Castillo <ibc@aliax.net> wrote:
> Hi, having the following file tree under my ext/ directory:
>
> my_ext/
>   extconf.rb
>   my_ext.c
>   utils/
>      utils.c
>      utils.h
>
> How to say in extconf.rb that files under utils/ subdirectory must
> also be compiled?

Though, IMO, there is no official way, here is a hack.
----------------------------------
require 'mkmf'

# set all object files to $objs before create_makefile.
$objs = ["my_ext.o", "utils/utils.o"]

create_makefile("my_ext")

# to clean up object files under util subdirectory.
open('Makefile', 'a') do |f|
  f.write <<EOS

CLEANOBJS := $(CLEANOBJS) utils/*.#{CONFIG["OBJEXT"]}
EOS
end
----------------------------------

I have tested this with ruby 1.9.3p194 on linux.
But it doesn't work for rubinius.