[Buildroot] [PATCH 3/4] Makefile: generate CMake toolchain file in $(O)

[Thomas Petazzoni]

Hello Bjorn,

On Fri, 7 Jan 2011 18:15:36 +0100
Thomas Petazzoni <thomas.petazzoni at free-electrons.com> wrote:

> diff --git a/Makefile b/Makefile
> index 831b424..994dd52 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -375,8 +375,11 @@ world: prepare dependencies dirs $(BASE_TARGETS)
> $(TARGETS_ALL) $(O)/toolchainfile.cmake:
>         @echo -en "\
>         set(CMAKE_SYSTEM_NAME Linux)\n\
> +       set(CMAKE_PROGRAM_PATH $(HOST_DIR)/usr/bin)\n\
>         set(CMAKE_C_COMPILER $(CMAKE_TARGET_CC))\n\
>         set(CMAKE_CXX_COMPILER $(CMAKE_TARGET_CXX))\n\
> +       set(CMAKE_C_FLAGS \"$(CMAKE_TARGET_CFLAGS)\")\n\
> +       set(CMAKE_CXX_FLAGS \"$(CMAKE_TARGET_CXXFLAGS)\")\n\
>         set(CMAKE_FIND_ROOT_PATH $(STAGING_DIR))\n\
>         set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)\n\
>         set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)\n\
> 
> With those, I can successfully use the CMake toolchain file to build a
> Qt application against the Buildroot libraries.
> 
> If you agree, could you merge those modifications into your patch ?

It'd be great if you could also add

	set(CMAKE_INSTALL_SO_NO_EXE 0)

This is related to the executable permission of the shared libraries
installed by CMake. As explained in Modules/Platform/Linux.cmake, the
behaviour of CMake depends on the host system: on Debian systems, it
installs shared libraries without executable permissions, and on Fedora
systems it installs shared libraries with executable permissions.

In Buildroot, all shared libraries are installed with executable
permissions, and this fact is used to support stripping of shared
libraries in the target-finalize target of the main Makefile.

Therefore, we should not rely on CMake default behaviour, and instead
tell CMake what to do: set the executable permission on the installed
shared libraries. Which is what is done by setting the above variable.

For reference, this issue has also been raised on OpenEmbedded:
http://www.mail-archive.com/openembedded-devel@lists.openembedded.org/msg04736.html.

Thanks!

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com