Date: Fri, 20 Aug 2004 15:36:05 +0300 From: Ruslan Ermilov <ru@FreeBSD.org> To: Oliver Eikemeier <eikemeier@fillmore-labs.com> Cc: current@FreeBSD.org Subject: Re: setting CFLAGS in /etc/make.conf Message-ID: <20040820123605.GD29568@ip.net.ua> In-Reply-To: <A8718F96-F2A1-11D8-A951-00039312D914@fillmore-labs.com> References: <p06110400bd4b837282da@[128.113.24.47]> <A8718F96-F2A1-11D8-A951-00039312D914@fillmore-labs.com>
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On Fri, Aug 20, 2004 at 02:08:33PM +0200, Oliver Eikemeier wrote:
> I run into this recently with mail/exim. Of course it was possible to
> work around this too, but it happened only when certain configuration
> options where given *and* CFLAGS was set in /etc/make.conf. There must
> be a better way to deal with this.
>
Facts:
1. In FreeBSD, CFLAGS (if not explicitly set, or set in /etc/make.conf)
is the global make(1) variable.
2. FreeBSD make(1) knows about environment and global variables, and
global variables take precedence over environment variables.
3. If CFLAGS is not explicitly set in /etc/make.conf, and CFLAGS is
set in environment instead, its value becomes a value of the CFLAGS
make(1) global variable:
: $ cat makefile
: FOO+= bar
:
: all:
: @echo global FOO: ${FOO}
: @echo env FOO: $${FOO}
: $ FOO=foo make
: global FOO: foo bar
: env FOO: foo
So, if you need to change another makefile's idea of the initial value
of CFLAGS, you basically have two reliable choices:
a) Don't use /etc/make.conf to avoid the possibility of setting
CFLAGS in /etc/make.conf.
b) Modify this another makefile to add things you want to CFLAGS;
the modification may be either hardcoded, or using another
macro whose value you can then pass as environment variable.
There's no other reliable way, and FreeBSD make(1) doesn't provide
you a way to initialize a variable in the global context on the
command line or from environment, except for -D which would set it
to "1". You can only modify global variables from makefile or
from its included sources.
P.S. I start to hate command-line variable in make(1). ;)
Cheers,
--
Ruslan Ermilov
ru@FreeBSD.org
FreeBSD committer
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