optionally include file within a Makefile

[Drew Eckhardt]

In message <3FE20A5C.2872.92C92363 at localhost>, dan at langille.org writes:
>On 18 Dec 2003 at 19:02, Dan Langille wrote:
>
>> My goal is provide a way to override values in a Makefile with values
>> from a local config file.
>
>I'm getting further.  What's the proper way to do an include?

The commands associated with a Make command are passed to the shell.

You need to do your conditional within the make environment, outside
of a rule

    .if exists foo
    .include foo
    .endif

    all: