[CMake] CMake finds wrong ar/ranlib/nm

[Auer, Jens]

Hi,

I am trying to use another compiler than the default one installed on my system. I have to do this because I want to use a newer gcc than the one on centos 7,so I installed RedHat Developer Toolset 3 with gcc 4.9. When I call cmake with
scl enable devtoolset-3 "cmake ../src" in my build directory, it generates makefiles which use the new compiler and linker, but still uses the default /usr/bin/ar etc. This is problematic because I enable whole-program-optimization in release mode, and this needs to use the ar provided with gcc 4.9 to handle the link-time optimization object files.

I have tried various things to force cmake to use a specific ar, but none of these worked:

-       Manually set CMAKE_AR in the CMakeLists.txt

-       Change CMAKE_AR in the cache

-       Write my own toolchain file
With the toolchain file, cmake creates Makefiles but puts an empty ar command in the lib "link" command, and building thus fails with an error.

Am I missing something?

Best wishes,
  Jens Auer


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