Mark NVBench headers as SYSTEM for consuming targets.

[alliepiper]

Fixes #30.

[oleksandr-pavlyk]

Left review comment at the parent issue: #30 (comment)

[alliepiper]

I talked with Rob offline and I'm planning to do the same pattern as CCCL with the system header pragmas. I'm working on this in the background on a local branch, just getting testing and stuff finished up.

[oleksandr-pavlyk]

@alliepiper Do you understand what causes compilation errors with CTK 12.9 and older GCC compilers and how to fix it?

Compilation commands

This PR ❌

/usr/bin/sccache /usr/local/cuda/bin/nvcc \
    -forward-unknown-to-host-compiler \
    -ccbin=/usr/bin/g++ \
    -DFMT_USE_BITINT=0 \
    -I/home/coder/nvbench \
    -I/home/coder/nvbench/build/cuda12.9-gcc7/nvbench-ci \
    -O3 -DNDEBUG -std=c++17 -arch=all-major \
    -Xcompiler=-fPIC -Xcompiler=-Wall -Xcompiler=-Wextra \
    -Xcompiler=-Wconversion -Xcompiler=-Woverloaded-virtual \
    -Xcompiler=-Wcast-qual -Xcompiler=-Wpointer-arith \
    -Xcompiler=-Wunused-local-typedefs -Xcompiler=-Wunused-parameter \
    -Xcompiler=-Wvla -Xcompiler=-Wno-gnu-line-marker \
    -Xcompiler=-Werror -Xcudafe=--display_error_number \
    -Wno-deprecated-gpu-targets -Xcudafe=--promote_warnings \
    -MD -MT nvbench/CMakeFiles/nvbench.main.dir/main.cu.o \
    -MF nvbench/CMakeFiles/nvbench.main.dir/main.cu.o.d \
    -x cu -c /home/coder/nvbench/nvbench/main.cu \
    -o nvbench/CMakeFiles/nvbench.main.dir/main.cu.o

Main ✅

/usr/bin/sccache /usr/local/cuda/bin/nvcc \
     -forward-unknown-to-host-compiler \
     -ccbin=/usr/bin/g++ \
     -DFMT_USE_BITINT=0 \
     -I/home/coder/nvbench \
     -I/home/coder/nvbench/build/cuda12.9-gcc7/nvbench-ci \
     -isystem /usr/local/cuda/targets/x86_64-linux/include \     # <-----
     -isystem /usr/local/cuda/include \                          # <-----
     -O3 -DNDEBUG -std=c++17 -arch=all-major \
     -Xcompiler=-fPIC -Xcompiler=-Wall -Xcompiler=-Wextra \
     -Xcompiler=-Wconversion -Xcompiler=-Woverloaded-virtual \
     -Xcompiler=-Wcast-qual -Xcompiler=-Wpointer-arith \
     -Xcompiler=-Wunused-local-typedefs -Xcompiler=-Wunused-parameter \
     -Xcompiler=-Wvla -Xcompiler=-Wno-gnu-line-marker \
     -Xcompiler=-Werror -Xcudafe=--display_error_number \
     -Wno-deprecated-gpu-targets -Xcudafe=--promote_warnings \
     -MD -MT nvbench/CMakeFiles/nvbench.main.dir/main.cu.o \
     -MF nvbench/CMakeFiles/nvbench.main.dir/main.cu.o.d \
     -x cu -c /home/coder/nvbench/nvbench/main.cu \
     -o nvbench/CMakeFiles/nvbench.main.dir/main.cu.o

[oleksandr-pavlyk]

I opened #330 that includes the commit from this PR and add a change to re-introduce linking of nvbench.main to CTK libraries to resolve the build break.