fix selection of possible include paths

src/Makefile

@@ -7,12 +7,6 @@ TARGET = libeclfft.a
 TARGET2 = libeclfft.so
 
 ifndef OPENCL_INCLUDE
-ifdef AMDAPPSDKROOT
-OPENCL_INCLUDE = $(AMDAPPSDKROOT)/include
-endif
-ifdef NVIDIA_SDK_INSTALL_PATH
-OPENCL_INCLUDE = $(NVIDIA_SDK_INSTALL_PATH)/OpenCL/common/inc
-endif
 ifdef CUDA_INSTALL_PATH
 OPENCL_INCLUDE = $(CUDA_INSTALL_PATH)/include
 endif
@@ -20,6 +14,9 @@ ifdef OPENCL_INSTALL_PATH
 OPENCL_INCLUDE = $(OPENCL_INSTALL_PATH)/include
 endif
 endif
+ifndef OPENCL_INCLUDE
+OPENCL_INCLUDE = $(AMDAPPSDKROOT)/include -I$(NVIDIA_SDK_INSTALL_PATH)/OpenCL/common/inc
+endif
 
 CXXFLAGS += -O3 -Wall -g -I$(OPENCL_INCLUDE) -I../include -fPIC
 OS = $(shell uname -s)