[Buildroot] RFC dependencies: checking minimum make version

[Buildroot] RFC dependencies: checking minimum make version

[Thomas De Schampheleire]

Hi,

The buildroot Makefile uses constructs like:

ifeq ($(BR2_TOOLCHAIN_BUILDROOT),y)
include toolchain/toolchain-buildroot.mk
else ifeq ($(BR2_TOOLCHAIN_EXTERNAL),y)
include toolchain/toolchain-external.mk
else ifeq ($(BR2_TOOLCHAIN_CTNG),y)
include toolchain/toolchain-crosstool-ng.mk
endif

which is supported from 3.81 onwards.
This means that make 3.80 will give a syntax error, even though the
toolchain/dependencies/dependencies.sh checks for minimal make version
(in fact, this script never gets a chance to run).

To fix this, and detect old make versions gracefully, I see following solutions:
1. Adapt our Makefiles to be make 3.80 compatible, by e.g. adapting
the above construct. This is not a waterproof solution, as a similar
but different problem may arise in the future.

2. Check for the make version in make instead of in shell, e.g. with
the following pattern: (adopted from
http://www.jgc.org/blog/cookbook-sample.pdf)
need := 3.81
ok := $(filter $(need),$(firstword $(sort $(MAKE_VERSION) $(need))))
ifeq (,$(ok))
$(error make too old!)
endif

This will not work when make 10.x comes out because of the sort trick,
but otherwise should work fine. This code should be included as early
as possible in the Makefile.


What do you think?

Thanks,
Thomas

[Buildroot] RFC dependencies: checking minimum make version

[Peter Korsgaard]

>>>>> "Thomas" == Thomas De Schampheleire <patrickdepinguin+buildroot@gmail.com> writes:

Hi,

 Thomas> 2. Check for the make version in make instead of in shell, e.g. with
 Thomas> the following pattern: (adopted from
 Thomas> http://www.jgc.org/blog/cookbook-sample.pdf)
 Thomas> need := 3.81
 Thomas> ok := $(filter $(need),$(firstword $(sort $(MAKE_VERSION) $(need))))
 Thomas> ifeq (,$(ok))
 Thomas> $(error make too old!)
 Thomas> endif

 Thomas> This will not work when make 10.x comes out because of the sort trick,
 Thomas> but otherwise should work fine. This code should be included as early
 Thomas> as possible in the Makefile.

 Thomas> What do you think?

The likelyhood of people using <3.81 is probably getting fairly small,
but I'm OK with such a test (with a better error message and variables
though)@the top of the main Makefile.

Out of interest, on what system did you hit this?

-- 
Bye, Peter Korsgaard

[Buildroot] RFC dependencies: checking minimum make version

[Thomas De Schampheleire]

On Thu, Dec 1, 2011 at 8:07 PM, Peter Korsgaard <jacmet@uclibc.org> wrote:
>>>>>> "Thomas" == Thomas De Schampheleire <patrickdepinguin+buildroot@gmail.com> writes:
>
> Hi,
>
> ?Thomas> 2. Check for the make version in make instead of in shell, e.g. with
> ?Thomas> the following pattern: (adopted from
> ?Thomas> http://www.jgc.org/blog/cookbook-sample.pdf)
> ?Thomas> need := 3.81
> ?Thomas> ok := $(filter $(need),$(firstword $(sort $(MAKE_VERSION) $(need))))
> ?Thomas> ifeq (,$(ok))
> ?Thomas> $(error make too old!)
> ?Thomas> endif
>
> ?Thomas> This will not work when make 10.x comes out because of the sort trick,
> ?Thomas> but otherwise should work fine. This code should be included as early
> ?Thomas> as possible in the Makefile.
>
> ?Thomas> What do you think?
>
> The likelyhood of people using <3.81 is probably getting fairly small,
> but I'm OK with such a test (with a better error message and variables
> though) at the top of the main Makefile.
>
> Out of interest, on what system did you hit this?

This problem was seen on a workstation in Shanghai, with an old RedHat
distribution (not sure which exactly, but the kernel was 2.6.9, so
pretty old).

I'll try to submit a patch one of these days.

Thanks,
Thomas

[Buildroot] RFC dependencies: checking minimum make version

[Peter Korsgaard]

>>>>> "Thomas" == Thomas De Schampheleire <patrickdepinguin+buildroot@gmail.com> writes:

Hi,

 >> Out of interest, on what system did you hit this?

 Thomas> This problem was seen on a workstation in Shanghai, with an old
 Thomas> RedHat distribution (not sure which exactly, but the kernel was
 Thomas> 2.6.9, so pretty old).

My guess would be RHEL4 (so from 2005).

 Thomas> I'll try to submit a patch one of these days.

Thanks.

-- 
Bye, Peter Korsgaard