Makefile: add dependancies for ffversion.h

It has to be build before the objects that use it
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Makefile

@@ -102,6 +102,8 @@ endef
 
 $(foreach P,$(PROGS),$(eval $(call DOPROG,$(P:$(PROGSSUF)$(EXESUF)=))))
 
+ffprobe.o cmdutils.o : libavutil/ffversion.h
+
 $(PROGS): %$(PROGSSUF)$(EXESUF): %$(PROGSSUF)_g$(EXESUF)
 	$(CP) $< $@
 	$(STRIP) $@