cm_cxx_features.cmake: icpc warnings fail unique_ptr tests on Crays
We're seeing this behavior building CMake on our Cray XC40 systems at LANL using the Intel Compiler. The warnings are misinterpreted as a feature failure of the C++ compiler.
Run Build Command(s):/usr/bin/gmake cmTC_12d5d/fast && gmake -f CMakeFiles/cmTC_12d5d.dir/build.make CMakeFiles/cmTC_12d5d.dir/build
gmake[1]: Entering directory '/tmp/jgreen/spack-stage/spack-stage-cmake-3.16.5-l3xjja467tr7zaac7w6wevskxzaiqmba/spack-src/CMakeFiles/CMakeTmp'
/usr/projects/hpctools/jgreen/spack/lib/spack/env/intel/icpc -std=gnu++17 -o CMakeFiles/cmTC_12d5d.dir/cm_cxx_make_unique.cxx.o -c /tmp/jgreen/spack-stage/spack-stage-cmake-3.16.5-l3xjja467tr7zaac7w6wevskxzaiqmba/spack-src/Source/Checks/cm_cxx_make_unique.cxx
icpc: command line warning #10121: overriding '-xCORE-AVX2' with '-march=haswell'
mp/jgreen/spack-stage/spack-stage-cmake-3.16.5-l3xjja467tr7zaac7w6wevskxzaiqmba/spack-src/Bootstrap.cmk/cmake -E cmake_link_script CMakeFiles/cmTC_12d5d.dir/link.txt --verbose=1
/usr/projects/hpctools/jgreen/spack/lib/spack/env/intel/icpc CMakeFiles/cmTC_12d5d.dir/cm_cxx_make_unique.cxx.o -o cmTC_12d5d
icpc: command line warning #10121: overriding '-xCORE-AVX2' with '-march=haswell'
gmake[1]: Leaving directory '/tmp/jgreen/spack-stage/spack-stage-cmake-3.16.5-l3xjja467tr7zaac7w6wevskxzaiqmba/spack-src/CMakeFiles/CMakeTmp'