[Buildroot] [PATCH 2/2] package/qemu: filter out long make options

[Thomas Petazzoni]

Hello,

On Wed, 21 Jul 2021 12:46:05 -0700
Alexey Neyman <stilor at att.net> wrote:

> Since qemu started using ninja, they have the following fragment in the
> Makefile:
> 
> MAKE.n = $(findstring n,$(firstword $(MAKEFLAGS)))
> NINJAFLAGS = ... $(if $(MAKE.n), -n) ...
> 
> Buildroot's generated makefile in the O= directory invokes make in the
> base buildroot with --no-print-directory. However, make's placement of
> the --no-print-directory in MAKEFLAGS varies between the versions of
> the host make; make 4.3 places that at the end while make 3.82 places
> it at the beginning. As a result, if building on a system with an older
> host make, qemu's makefile invokes `ninja -n` which does not generate
> any outputs.
> 
> To reproduce, on a CentOS 7 machine or docker image:
>   mkdir /tmp/br-build && cd /tmp/br-build
>   make -C ~/buildroot pc_x86_64_bios_defconfig O=`pwd`
>   make menuconfig # Switch to glibc, enable "QEMU" and "QEMU tools"
>   make all # Build succeeds
>   find target -name qemu-img # No binary has been built

I'm not sure to grasp all the implications of this, but isn't this a
bug in Qemu's build machinery, that should be fixed in Qemu's Makefile
instead ?

Thomas
-- 
Thomas Petazzoni, co-owner and CEO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com