simplify lzo-test rule

Originally committed as revision 12269 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavutil/Makefile

@@ -45,8 +45,7 @@ TESTS = $(addsuffix -test$(EXESUF), adler32 aes crc des lls md5 sha1 softfloat t
 
 include ../common.mak
 
-lzo-test$(EXESUF): lzo.c $(LIBNAME)
-	$(CC) $(CFLAGS) $(LDFLAGS) -DTEST -o $@ $^ $(EXTRALIBS) -llzo2
+lzo-test$(EXESUF): EXTRALIBS += -llzo2
 
 clean::
 	rm -f lzo-test$(EXESUF)