[Buildroot] [PATCH v2 1/1] package/pkg-cmake: Use CMAKE_<LANG>_COMPILER_LAUNCHER for ccache

[Daniel Black]

Hey Arnout,

On 11/03/17 10:25, Arnout Vandecappelle wrote:
> 
> 
> On 09-03-17 06:07, Daniel Black wrote:
>> Since cmake version 3.4.0 CMAKE_<LANG>_COMPILER_LAUNCHER is used as
>> the way to invoke things like ccache. We set this to ccache for
>> the host and for cross compilers in toolchain.cmake.in. This
>> leaves CMAKE_<C,CXX>_COMPILER pointing at the real compiler and
>> still uses ccache.
>>
>> Update minimium dependency version in check-host-cmake.mk accordingly.
> 
>  This is very unfortunate, it means a substantial slowdown in the build for
> people who have an older system CMake.

I didn't think it was that substantial for a one-off host package
upgrade. I do realize it is a non-zero imposition for that installed
cmake before it was updated to 3.4.0 in
7453c4bf6010b3a8dd794c39e327641abea15503 (Nov 13 2015).

>  Although it is indeed cleaner to handle ccache this way, I don't think it
> really fixes anything, does it?

Might fix some subtle build errors for packages that do odd things
however no, there isn't an definite breakage I can point to.

> In that case, I think we should just stick with
> the old way of doing things. We can revisit when we need to CMake 3.4 for some
> other package.

Works for me.