Changing the compilation arguments passed to nvcc by Rust using cc - cuda

Question

I am using cc to link a CUDA kernel written in C to Rust.
Here is my build.rs file:
extern crate cc;
fn main() {
cc::Build::new()
.cuda(true)
.flag("-cudart=shared")
.flag("-gencode")
.flag("arch=compute_61,code=sm_61")
.file("kernel/kernel.cu")
.compile("kernel/kernel.a");
}
I have this error :
running: "nvcc" "-ccbin=c++" "-O0" "-Xcompiler" "-ffunction-sections"
"-Xcompiler" "-fdata-sections" "-Xcompiler" "-fPIC" "-G" "-Xcompiler"
"-g" "-m64" "-Xcompiler" "-Wall" "-Xcompiler" "-Wextra"
"-cudart=shared" "-gencode" "arch=compute_61,code=sm_61" "-o"
"/home/ltei/Dev/Workspaces/rust_cudnn/target/debug/build/rust_cudnn-df924982e63c2363/out/kernel/kernel.o"
"-c" "kernel/kernel.cu" cargo:warning=In file included from
/usr/include/cuda_runtime.h:78:0, cargo:warning= from
:0: cargo:warning=/usr/include/host_config.h:119:2:
error: #error -- unsupported GNU version! gcc versions later than 5
are not supported! cargo:warning= #error -- unsupported GNU version!
gcc versions later than 5 are not supported! cargo:warning= ^~~~~
exit code: 1
I know that it would work if I could change the -ccbin=c++ in the command into -ccbin=clang-3.8, but I have no idea how to do it.
I could also install another version of GCC, but I'd prefer the first solution.

Answer 1

You can set the CXX environment variable to whatever you want.
CXX=this-is-my-cpp-compiler cargo build
This will be used as the argument to ccbin:
"nvcc" "-ccbin=this-is-my-cpp-compiler" "-O0" "-Xcompiler" "-ffunction-sections" "-Xcompiler" "-fdata-sections" "-Xcompiler" "-fPIC" "-G" "-Xcompiler" "-g" "-m64" "-Xcompiler" "-Wall" "-Xcompiler" "-Wextra" "-cudart=shared" "-gencode" "arch=compute_61,code=sm_61" "-o" "/private/tmp/c/target/debug/build/c-67ec4fdcff2f35d1/out/kernel/kernel.o" "-c" "kernel/kernel.cu"