toochainfile.cmake: rework the way Buildroot sets flags

From the build configuration, Buildroot defines and set some compiler
and linker flags that should be passed to any packages build-system.

For package using the cmake-package infrastructure, this is achieved
via the toolchainfile.cmake.

This change simplifies the way the toolchainfile.cmake file handles
these flags: it now just sets them, without any attempt to extend them
with those Buildroot defined.

This change still allows overriding these flags from the configure
command line.

So, now, when a CMake-based package needs to extend them, they should
be fully set from the package *.mk file. This behavior is consistent
with what is done for others package infrastructures.

This change should not pull any regression WRT the bug #7280 [1].

However, now, when someone uses the toolchainfile.cmake file outside of
Buildroot, he/she must overload all compiler/linker flags (including the
ones Buildroot sets since they no longer get automatically added).

[1] https://bugs.busybox.net/show_bug.cgi?id=7280

Cc: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Samuel Martin <s.martin49@gmail.com>
Reviewed-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/CHANGES b/CHANGES
index 284a65460..fd5abcb8e 100644
--- a/CHANGES
+++ b/CHANGES
@@ -3,7 +3,8 @@
 	CMake support:
 
 	The toolchainfile.cmake file now provides a definition of the
-	CMAKE_BUILD_TYPE variable.
+	CMAKE_BUILD_TYPE variable. The toolchainfile.cmake also no
+	longer passes the compiler/linker flags defined by Buildroot.
 
 2016.08, Released September 1st, 2016