Makefile: Make all output files depend on the Makefile itself

If you now rerun ./configure (e.g. for a different --prefix), everything
will be recompiled.


git-svn-id: https://znc.svn.sourceforge.net/svnroot/znc/trunk@1205 726aef4b-f618-498e-8847-2d620e286838

modules/Makefile.in

@@ -70,7 +70,7 @@ install_metadirs: create_install_dir
 clean:
 	rm -rf $(CLEAN)
 
-%.so: %.cpp
+%.so: %.cpp Makefile
 	@mkdir -p .depend
 	$(CXX) $(MODFLAGS) $(INCLUDES) $(LDFLAGS) -shared -o $@ $< $($(basename $<)FLAGS) -MMD -MF .depend/$<.dep