Cleaning up some warnings and enabling -Werror on CPU CI tests #196

Job	Run time
lint	13s
check_docker_files / check_docker_files	4s
build_base	0s
build (openmp, gcc, gcc, g++, -DKokkos_ENABLE_OPENMP=ON, -DCMAKE_CXX_FLAGS="-Wall -Wextra" -DCMAK...	58s
build (threads, gcc, gcc, g++, -DKokkos_ENABLE_THREADS=ON, -DCMAKE_CXX_FLAGS="-Wall -Wextra" -DCM...	1s
build (serial, gcc, gcc, g++, -DKokkos_ENABLE_SERIAL=ON, -DCMAKE_CXX_FLAGS="-Wall -Wextra" -DCMAK...	1s
build (cuda, nvcc, gcc, g++, -DKokkos_ENABLE_CUDA=ON -DKokkos_ARCH_AMPERE80=ON, native)	1m 19s
build (cuda, nvcc, gcc, g++, -DKokkos_ENABLE_CUDA=ON -DKokkos_ARCH_AMPERE80=ON, host_device, -DKo...	2m 51s
build (hip, rocm, hipcc, hipcc, -DKokkos_ENABLE_HIP=ON -DKokkos_ARCH_VEGA90A=ON, -DKokkosFFT_ENAB...	31s
build (hip, rocm, hipcc, hipcc, -DKokkos_ENABLE_HIP=ON -DKokkos_ARCH_VEGA90A=ON, -DKokkosFFT_ENAB...	2m 52s
build (rocm, rocm, hipcc, hipcc, -DKokkos_ENABLE_HIP=ON -DKokkos_ARCH_VEGA90A=ON, native)	1s
build (rocm, rocm, hipcc, hipcc, -DKokkos_ENABLE_HIP=ON -DKokkos_ARCH_VEGA90A=ON, host_device, -D...	26s
build (sycl, intel, icx, icpx, -DKokkos_ENABLE_SYCL=ON -DKokkos_ARCH_INTEL_GEN=ON, native)	1s
build (sycl, intel, icx, icpx, -DKokkos_ENABLE_SYCL=ON -DKokkos_ARCH_INTEL_GEN=ON, host_device, -...	1s
test	0s
	9m 19s

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