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Date: Tue, 10 Jun 2014 11:50:17 +0200
From: Sam Ravnborg <sam@ravnborg.org>
Subject: Re: [PATCH] kbuild: document KBUILD_SHELL
Message-ID: <20140610095016.GA5528@ravnborg.org>
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To: Michal Marek <mmarek@suse.cz>
Cc: Masahiro Yamada <yamada.m@jp.panasonic.com>, linux-kbuild@vger.kernel.org

> 
> The variable is assinged with a ":=", not a "?=", so you can't change it
> from outside, can you?

Variables assigned with ":=" can be changed like this:

$ cat Makefile
FOO := fisk
$(info FOO=$(FOO))
all:
	@:

$ FOO=bar make
FOO=fisk

$ make FOO=bar
FOO=bar


The first is the same as using an environment variable.
The latter is a special make syntax.

	Sam