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Date: Mon, 6 Feb 2017 12:23:12 +0000
From: "Daniel P. Berrange" <berrange@redhat.com>
Message-ID: <20170206122312.GL3029@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH] rules: don't try to create missing include
 dirs
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To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Maydell <peter.maydell@linaro.org>, QEMU Developers <qemu-devel@nongnu.org>, Alberto Garcia <berto@igalia.com>, Stefan Hajnoczi <stefanha@redhat.com>

On Mon, Feb 06, 2017 at 01:22:08PM +0100, Paolo Bonzini wrote:
> 
> 
> On 06/02/2017 13:05, Daniel P. Berrange wrote:
> >>>          $(shell mkdir -p ./ $(sort $(dir $($v))))
> >>> -        $(shell cd $(BUILD_DIR) && mkdir -p ./ $(sort $(dir $($v))))
> >> I know this is the same syntax as the existing line above
> >> and we're deleting it anyway, but what does it actually do?
> >> When does telling mkdir to create "./" make sense?
> > No idea why the ./ was there originally - it appears to serve no
> > purpose. The useful bit is the stuff afterwards - the $($v) bit.
> > It gets populated based on the variable being unnested. For example
> > 
> >    block-obj-y = block.o blockjob.o block/ nbd/
> > 
> > will make $v contain  "block nbd", hence cause creation of those
> > dirs in the the build dir.
> 
> "mkdir -p" with no arguments gives an error, the "./" shuts it up.

Ah yes, clever. So that deals with case of unnesting a variable which
does not contain any nested dirs.

Regards,
Daniel
-- 
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