Merge remote-tracking branch 'nccl/v2.19' into develop

src/include/param.h

@@ -13,6 +13,7 @@
 const char* userHomeDir();
 void setEnvFile(const char* fileName);
 void initEnv();
+const char *ncclGetEnv(const char *name);
 
 void ncclLoadParam(char const* env, int64_t deftVal, int64_t uninitialized, int64_t* cache);