Merge remote-tracking branch 'nccl/master' into develop

Makefile

@@ -7,9 +7,9 @@
 BUILDDIR ?= build
 override BUILDDIR := $(abspath $(BUILDDIR))
 
-.PHONY : all clean
+.PHONY: all clean
 
-default : src.build
+default: src.build
 
 TARGETS=$(filter-out src/hypercube.cu, $(wildcard src/*))