[Buildroot] [PATCH v6 18/28] package/cmake: Fix for using -O in top-level make

[Thomas Petazzoni <thomas.petazzoni@bootlin.com>]

On Thu, 19 Mar 2020 13:40:36 +0200
Asaf Kahlon <asafka7@gmail.com> wrote:

> > To me it seems like this could be the culprit. The question is, what
> > should we do with this? Check for Make version < 4.2 && -j && -O and
> > give a warning? Maybe this is a bit too much.  
> We now check for make>4.0. Do we want to bump it?
> Maybe some of the core Buildroot maintainers can give their advice here.

We don't require make 4.0, we only require make 3.81.

The logic in support/dependencies/check-host-make.mk to check for make
4.0 is only for those few packages that do need make >= 4.0. For such
packages, if the version of make installed system-wide is < 4.0, then
we build our own host-make. But the overall Buildroot build is still
executed by the system-wide make, which may be < 4.0.

Requiring make > 4.0 on the host system is too strict, especially
considering that the issue we have here only happens in very specific
conditions: ccache support enabled, and passing of custom -O flags that
are only useful for top-level parallel build, which is itself an
experimental feature.

Best regards,

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