Change __CUDACC_VER_*__ preprocessor directives to CUDA_VERSION because clang doesn't define the former.

src/include/common_coll.h

@@ -18,7 +18,7 @@ static ncclResult_t PointerCheck(const void* pointer, struct ncclComm* comm, con
     WARN("%s : %s is not a valid pointer", opname, ptrname);
     return ncclInvalidArgument;
   }
-#if __CUDACC_VER_MAJOR__ >= 10
+#if CUDA_VERSION >= 10000
   if (attr.type == cudaMemoryTypeDevice && attr.device != comm->cudaDev) {
 #else
   if (attr.memoryType == cudaMemoryTypeDevice && attr.device != comm->cudaDev) {

src/include/core.h

@@ -18,7 +18,7 @@
 #include <stdlib.h>
 #include <cuda_runtime.h>
 
-#if __CUDACC_VER_MAJOR__ < 9
+#if CUDA_VERSION < 9000
 struct cudaLaunchParams {
   void *func;
   dim3 gridDim;