Disable MSCCL kernels at compile time (#834)

* Disable MSCCL kernels at compile time

src/misc/msccl/msccl_lifecycle.cc

@@ -30,7 +30,11 @@ static bool mscclSchedulerTriedLoadAlgo = false;
 static std::mutex mscclLifecycleMutex;
 
 bool mscclEnabled() {
+#ifdef COMPILE_MSCCL_KERNEL
   return rcclParamMscclEnabled();
+#else
+  return false;
+#endif
 }
 
 void mscclSetIsCallerFlag() {

src/misc/msccl/msccl_setup.cc

@@ -9,7 +9,9 @@
 #include "transport.h"
 
 #include "msccl/msccl_lifecycle.h"
+#ifdef COMPILE_MSCCL_KERNEL
 #include "msccl/msccl_kernel.h"
+#endif
 #include "msccl/msccl_setup.h"
 #include "msccl/msccl_status.h"
 
@@ -243,7 +245,9 @@ static ncclResult_t hostToDevRedOp(
 
 // Except for ncclDevPreMulSum and ncclDevSumPostDiv required by ncclAvg
 void* mscclKernelEntries[(ncclNumDevRedOps - 2) * ncclNumTypes * NCCL_NUM_PROTOCOLS] = {
+#ifdef COMPILE_MSCCL_KERNEL
   MSCCL_KERNEL_ENTRY()
+#endif
 };
 
 ncclResult_t mscclSetupKernel(const void* sendBuff, void* recvBuff, size_t count,