OOOPS! Make sure that we touch the .done even if the directory already exists. This will fix the constant rebuild problem

config/rules.mk

@@ -1096,7 +1096,8 @@ export:: $(XPIDLSRCS) $(DIST)/idl
 # generate .h files from into $(XPIDL_GEN_DIR), then export to $(PUBLIC);
 # warn against overriding existing .h file. 
 $(XPIDL_GEN_DIR)/.done:
-	@if test ! -d $(XPIDL_GEN_DIR); then echo Creating $(XPIDL_GEN_DIR)/.done; rm -rf $(XPIDL_GEN_DIR); mkdir $(XPIDL_GEN_DIR); touch $@ else true; fi
+	@if test ! -d $(XPIDL_GEN_DIR); then echo Creating $(XPIDL_GEN_DIR)/.done; rm -rf $(XPIDL_GEN_DIR); mkdir $(XPIDL_GEN_DIR); fi
+	@touch $@
 
 # don't depend on $(XPIDL_GEN_DIR), because the modification date changes
 # with any addition to the directory, regenerating all .h files -> everything.