diff --git a/makefiles/common.mk b/makefiles/common.mk
index 37e81be..2e44826 100644
--- a/makefiles/common.mk
+++ b/makefiles/common.mk
@@ -42,9 +42,10 @@ else
 endif
 #$(info NVCC_GENCODE is ${NVCC_GENCODE})
 
-CXXFLAGS   := -DCUDA_MAJOR=$(CUDA_MAJOR) -DCUDA_MINOR=$(CUDA_MINOR) -fPIC -fvisibility=hidden
-CXXFLAGS   += -Wall -Wno-unused-function -Wno-sign-compare -std=c++11 -Wvla
-CXXFLAGS   += -I $(CUDA_INC)
+CXXFLAGS   := -DCUDA_MAJOR=$(CUDA_MAJOR) -DCUDA_MINOR=$(CUDA_MINOR) -fPIC -fvisibility=hidden \
+              -Wall -Wno-unused-function -Wno-sign-compare -std=c++11 -Wvla \
+              -I $(CUDA_INC) \
+              $(CXXFLAGS)
 # Maxrregcount needs to be set accordingly to NCCL_MAX_NTHREADS (otherwise it will cause kernel launch errors)
 # 512 : 120, 640 : 96, 768 : 80, 1024 : 60
 # We would not have to set this if we used __launch_bounds__, but this only works on kernels, not on functions.