don't force building the static version when installing

src/Makefile

@@ -52,7 +52,7 @@ fft_execute.o: fft_execute.cpp ../include/clFFT.h fft_internal.h
 fft_kernelstring.o: fft_kernelstring.cpp ../include/clFFT.h fft_internal.h
 	$(CXX) $(CXXFLAGS) -c fft_kernelstring.cpp
 
-install: $(TARGET) ../include/clFFT.h
+install: ../include/clFFT.h libeclfft.*
 	mkdir -p $(PREFIX)/lib $(PREFIX)/include
 	cp  ../include/clFFT.h $(PREFIX)/include/eclfft.h
 	cp  libeclfft.* $(PREFIX)/lib/