Don't use 'rm -f *$(SLIBSUF)' in a clean rule, $(SLIBSUF) might be empty.

Remove all possible shared libs suffixes instead.

Originally committed as revision 4860 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/Makefile

@@ -143,7 +143,7 @@ install-headers:
 	g++ $(subst -Wall,,$(CFLAGS)) -c -o $@ $<
 
 distclean clean:
-	rm -f *.o *.d .depend *~ *.a *$(SLIBSUF) $(LIB)
+	rm -f *.o *.d *~ .depend *.a *.lib *.so *.dylib *.dll
 
 #
 # include dependency files if they exist